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Topic: 8th grade Algebra help! Please!?**Question:**
I know how to do it, but now these expressions are getting longer and more confusing. And I'm just getting stumped =/ Can you explain how to do these for me PLEASE?
9(a+b) + 4(3a+2b)
8(k+m)+15(2k+5m)
6(r+5)+9(r-2)-4r
4(n+7)+5(n-3)-2n
7(c+2d+8)+3(9c-2)
4(5x+3y+6)+14(2y-1)
Thanks!! ~Laya♥

June 16, 2019 / By Astra

Hi Laya S. : That okay, I understand but I help you with one of the them but you got do the rest. My advise : Please do them one at a time. and take your time in doing them It not the speed at which the lesson is learned - but that it is learned. Okay. Given 6(r+5)+9(r-2)-4r - original equation Step 1 : 6(r+5)+9(r-2)-4r - original equation 6r+30 + 9r - 18 - 4r - Multiplication 9r+6r-4r +30 -18 - Rearrange the equation to get like terms together 15r- 4r + 12 - Addition 11r +12 - Addition again Answer : 11r +12 proof: Let prove the equation 11r +12 = 6(r+5)+9(r-2)-4r of original equation given in the above is true by making r = 2 6(r+5)+9(r-2)-4r - original equation 11r +12 - derived equation from the above since we want to see if the equal each other to prove it so: 6(r+5)+9(r-2)-4r = 11r +12 Do ing the above to equal each other 6(2+5) + 9(2-2) - 4(2) = 11(2) +12 - Substituting r with 2 6(7) + 9(0) - 8 = 22+12 - Addition 42 + 0 - 8 = 34 - Multiplication 34 = 34 - Addition It checks and equals Therefore the equation 11r +12 is the same equation 6(r+5)+9(r-2)-4r and it true for for all values of r My tips for doing this: My tips: 1) read the problem through; until you understand it. 2) look for clue words like: sum, more than,less than, greater,multiplied,divided by..ect for all word problems 3) look for given equation, variables, etc 4) find out what the problem is asking you to solve for . 5) write "Given: " , than what is given, than write what your sloving for 6) if you have to rearrange the equation in order to slove it, than write out step by step what math operation your using on it to solve it, if you have to rearrange it otherwise to 7 7) Write step by step what Math operation your using to slove for it . This will make it easier for you to backtrack it and see what you did wrong; if you made error in your math - if your proof for it , doesn't check and equal 8) While doing number 6 and 7: Pay Attention To the Signs . This the one number reason why people make a errors in Math answers when solving there math problem 9) Do a Proof to prove your answer is correct By writting "Proof:" - The reason for this : Sometimes you might think you have the right answer when your really got the wrong one but this will tell you right away. do the following: 10) write your original equation down ,plug in your numbers, than write step by step what Math operation your using to solve for it . If this does not check and equal than back track for your answer in the frist part it they check out than check the Proof and see if you made a error . as soon as you find your error . Correct it than solve it again and redo the proof again until it check and equals 11) if your not sure of how to do a problem , ask a good friend or a good teacher who is good in math to help you okay 12) Sometime ask the web for help, you want to find the surface area of a cone; just type in "Surface area of a cone" in one of the search engine boxes press enter and see what pops up click a few of them and see if you can find the equation Wikpika - is a good source for math, help so is yahoo, bing is a hit and miss but they can be a big help. once you find the equation- write it down along with what is in a notebook and you will have it at side ready to aid in your time of confession or dougt, okay. Just be sure to add any other equations you encounter in math and they always be ready to assits you like a flaming sword makes a enemy stop in his track so will this aid you. 13) Make sure you put the units on the end of the final answer . Some teacher will mark it wrong if it not there Here a example of of a math problem so you get a idea of how to do one : example: A spherical tank need to hold 100 cubic feet of water, using the formula V= 4/3*pi*r^3 , and pi = 3.14159258, what is the radius of the tank: step 1 Given : pi = 3.14159258 V = 4/3 * pi* r^3 V= 100 where sloving for r Step 2 V = 4/3 * pi* r^3 - original equation 100 = 4/3* 3.14159258 * r^3 - Substitution of V, and pi 100* 3/4 = 4/3* 3.1415258 * r^3 * 3/4 - Multiplying the multiplicative inverse of a number to both sides of the equation to move it to the other side of it 300/4 = 3.14159258 * r^3 - Multiplication 75 = 3.14159258 * r^3 - Division 75 * 1/3.14159258 = 3.14159258* r^3 * 1/3.14159259 - Multiplying the multiplicative inverse of a number to both sides of the equation to move it to the other side of it 75/3.14159258 = r^3 - Multiplication 23.873242023000 = r^3 - Division 23.873242023000 ^ (1/3) = (r ^ 3)^(1/3) - taking the cube root of both sides of the equation to remove the cube 2.879411933968 = r - doing or solving the cube root The answer for r is 2.879411933968 feet Proof

👍 114 | 👎 3

Did you like the answer? 3x + 4xy + 5 x = 4/3 y = 3/2 Plug in the values of x and y and simplify. 3(4/3) + 4(4/3)(3/2) + 5 = 4 + 4(12/6) + 5 = 4 + 4(2) + 5 = 4 + 8 + 5 = 17

Okay, (: this is what i am did last yearrr . soo lets take the first one for example, 9(a+b) + 4(3a+2b) the first thing you must do is distribute the 9, to do this you multiple the 9 by a abd b. the equation is now : 9a+9b+4(3a+2b) next, you distribut the 4. to do this you multiply 4 by 3a and 2b. 9a+9b+12a+8b now you simplify like terms! like terms are the ones with the same variables. so 91 and 12 a are lkike terms, as well as 9b and 8b. your final answer will be : 21a+17b here are the steps to the second one : 8(k+m) + 15(2k+5m) 8k+8m+15(2k+5m) 8k+8m+30k+75m 38k+83m i will also show you the steps to one of the harder ones - 4(5x+3y+6)+14(2y-1) 20x+12y+24+28y-14 20x+40y+10 GOOD LUCK, (: hope i helped you!

👍 40 | 👎 -4

When you see an algebraic term like 9(a+b), it means that before you can add it to another term or do anything else with it, you must multiply the 9 times the a and then the b. Example: 9 times a =9a. 9 times b = 9b. Then combine them: 9a+9b. Do the same with the 4(3a+2b) 4 times 3a = 12a; 4 times 2b = 8b; combine them: 12a+8b Now combine the two terms: 9a + 9b +12a +8b _________ 21a + 17b do the same thing for the rest paying attention to the negative/positive signs. good luck

👍 38 | 👎 -11

9(a+b) + 4(3a+2b) First, distribute. 9a+9b + 12a+8b Then simplify the like terms. 21a + 17b 8(k+m) + 15(2k+5m) Again, distribution first. 8k+8m + 30k+75m Simplify. 38k + 83m 6(r+5) + 9(r-2)-4r Distribute. 6r+30 + 9r-18-4r Simplify. 11r+12 4(n+7) + 5(n-3)-2n. Distribute. 4n+28 + 5n-15-2n Simplify. 7n + 13 7(c+2d+8) + 3(9c-2) Distribute. 7c+14d+56 + 27c-6 Simplify. 33c+14d+50 4(5x+3y+6) + 14(2y-1) Distribute. 20x+12y+24 + 28y-14 Simplify. 20x+40y+10. Kay, I hope these are all right and help you understand a bit more...I'm not really great at the explaining, but I hope I helped a little.

👍 36 | 👎 -18

Do you want them simplified for you, or to learn it yourself? I hope the second one, because grade nine takes this and adds another level of pain, haha :) Ok, for the first one. The nine will times itself with the a and the b, turning into 9a + 9b. The four will do the same, and become 12a + 8b. Adding together the like terms (9a + 12a and 9b + 8b) you'll wind up with the answer of 21a + 17b. The rest of the equations are basically the same thing, so if you get the gist of like terms and mulitplying the inside by the number outside then adding the results, you'll be fine. I know it's hard to wrap your head around, but after you do, it'll free flow like nothing else. I hope this helps, and good luck on homework and any following tests/assignments! : )

👍 34 | 👎 -25

Just add together the like terms: 7a^3 + 3a^2 - a + 2 + 8a^2 - 3a - 4 7a^3 + 3a^2 + 8a^2 - a - 3a + 2 - 4 7a^3 + 11a^2 - 4a - 2

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