posted by .

If the answer is 1-2/3m what is the question>

How can you solve equations like these?

9r + 7 = 4r - 8

Need to get the r on one side.
1st- subtract 4r from the right side of the = sign. What you do to one side do to the other. 9r-4r+7=4r-4r-8. 5r+7=-8
2nd- subtract 7 from the left side to get r's by themselves. 5r+7-7=-8-7....5r=-15.
Divide 5r by 5.....remeber do it to both sides......5r/5=-15/5......r=-3
check answer.

Thanks for your help. I'm completely lost. Can you explain how 9r+7 = 4r-8?

  • math -


  • math -


  • math -

    what is rule for input value of n?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Substitution Method

    Use the Substitution method to solve the system of equations. x + y = -4 x - y = 2 x + y = -4 x - y = 2 In the second equation, x= y+2 Putting that in the first.. (y+2) + y= -4 subtract two from each side, then divide each side by …
  2. Algebra

    I don't understand how to do this problems: Solve for the variable r, C=2PIr (PI is the pi symbol thing then r is next to it) and this problem solve for the variable l, S=B+1/2Pl please help :) When you solve for a variable, you want …
  3. Math

    Solve for X: 4x - 2 +7 = 17 collect like terms on left hand side 4x + 5 = 17 subtract 5 from each side 4x = 12 divide by 4 on each side x = 3
  4. math--pre alg

    not sure i did right 3(f+2)+9=13+5f 3f+6+9 = 13+5f +9 3F+15 = 12+5F GOT MIXED UP SOMWERE HELP 3f +6 +9 = 13 + 5f 3f + 15 = 13 + 5f 2f = 2 f = 1 drwls is correct You are doing OK up to this point: 3f + 6 + 9 = 13 + 5f Now combine any …
  5. algebra

    I need a step by step explanation on how to add these two equations 2x+3y=1 5x+3y=16 Subtract the first equation from the second. (Subtract left and right sides separately). This gives you 3x = 15 Then divide both sides by 3. x = 5 …
  6. math

    2x+4(1-x)=11+5x 2x+4-4x=11+5x 6x+4=11+5x 6x=7+5x x=7 i think this is it x = 7 is not correct. Here's how the problem should work out: Use the distributive property to get rid of the parentheses and you will end up with this: 2x + 4 …
  7. Math

    You are given two equations which are both true, and you are asked to solve for both x and y. You plan to solve this set of equations by substituting part of one equation into the other so you end up with an equation that contains …
  8. Basic Math

    I forgot how to solve for two variables... Please check if I solved both problems properly! Thank you. Equations: (solve for t and z) 12t + 4z = 80 2t + 4z = 20 My answer: t = 2, z = 14 The steps: (simplified it) z = 20 - 3t, z = 5 …
  9. algebra 2

    how do you solve quadratic equations by finding square roots i have no clue how to do this. I have fallen behind in my math class because my teacher is horrible. I need to learn this to understand everything in the section in the section. …
  10. algerbra

    am i correct on this? question: solve and check square of 5x+6 is equal to x work and answer: square each side 5x+6=x^2 subtract 5x-6 on both sides 0=x^2-5x-6 (x+1)(x-6) x+1=0 subtract -1 on each side x= -1 is a reject x-6=0 add 6

More Similar Questions