234k views
3 votes
PLZ ANSWER FAST. Find the solution of this system of the equations

-3x-7y=-66
-10x-7y=-24

User AvahW
by
5.8k points

2 Answers

4 votes

Given system of equations:


\left \{ {{-3x~-~7y~=~-66} \atop {-10x~-~7y~=~-24}} \right.

  • Let's solve this system of equations using the substitution method. Solve for y in the first equation.

-3x - 7y = -66

  • Add 3x to both sides.

-7y = -66 + 3x

  • Divide both sides by -7.

y = 66/7 - 3/7x

  • Plug y into the second equation.

-10x - 7(66/7 - 3/7x) = -24

  • Distribute 7 inside the parentheses.

-10x - 66 + 3x = -24

  • Combine like terms on the left side of the equation.

-7x - 66 = -24

  • Add 66 to both sides.

-7x = 42

  • Divide both sides by -7.

x = -6

  • Plug -6 for x into the first equation.

-3(-6) - 7y = -66

  • Multiply -3 * -6.

18 - 7y = -66

  • Subtract 18 from both sides.

-7y = -84

  • Divide both sides by -7.

y = 12

Your answer is:

  1. x = -6
  2. y = 12
User Laur
by
4.6k points
2 votes

For this, I will be using the elimination method. So with this, subtract the second equation from the first equation to get
7x=-42 . From here you can solve for x.

For this equation, just divide both sides by 7, and your first answer is
x=-6

Now that we have the value of x, substitute it into either equation to solve for y:


-3(-6)-7y=-66\\ 18-7y=-66\\ -7y=-84\\ y=12\\ \\ -10(-6)-7y=-24\\ 60-7y=-24\\ -7y=-84\\ y=12

In short, x = -6 and y = 12.

User ToastyMallows
by
6.0k points