Question

I DON'T UNDERSTAND!!!!!!!

Find the solution to the system of equations.
−7x−2y=14

6x+6y=18

x=

y=

Answer 1

x = - 4, y = 7

Explanation:

Given the 2 equations

-7x - 2y = 14 → (1)

6x + 6y = 18 → (2) ← Divide all terms by 6

x + y = 3 ← rearrange expressing x in terms of y, subtract y from both sides

x = 3 - y → (3)

Substitute x = 3 - y into (1)

- 7(3 - y) - 2y = 14

- 21 + 7y - 2y = 14

- 21 + 5y = 14 ( add 21 to both sides )

5y = 35 ( divide both sides by 5 )

y = 7

Substitute y = 7 into (3) for corresponding value of x

x = 3 - 7 = - 4

Answer 2

x=-4 and y=7

Explanation:

So the equations are -7x-2y=14 and 6x+6y=18

there are multiple ways to solve this equation:

you can either first isolate a variable and then substitute it in kind of like what I showed you in the last one of these (since I showed you this one I will show you the other)

OR

you can cancel out some variables.

THE CANCELATION METHOD

for this method you need to make one of the variables in one equation be opposite of the same variable in the other equation (for example 2x is the opposite of -2x)

We can multiply the first equation by 3

-21x-6y=42 (this is the first equation multiplied by 3)

6x+6y=18 (this is the second equation)

now you add the two equations together

-15x=60

See how the two y values cancel out?

divide both sides by -15

x=-4

substitute this into one of the original equations

6(-4)+6y=18

-24+6y=18

add 24 to both sides

6y=42

divide both by 6

y=7

ALWAYS check your answers

6(-4)+6(7)=18

-24+42=18

18=18