If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to y from the first equation is substituted into the second equation.

8x − y = −9
4x − 3y = −22

Question

If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to y from the first equation is substituted into the second equation.

8x − y = −9 
4x − 3y = −22

welshfella · Answer

8x - y = -9
we need to isolate y  so first subtract 8x from both sides
8x - 8x - y = -9 - 8x
- y = -8x - 9

now to get y we divide  both sides of the above by -1

welshfella · Answer

just divide -y,  -8x and -9 by -1

katecc379 · Answer

so y=8x+9

welshfella · Answer

correct

katecc379 · Answer

4(−8x − 9) − 3y = −22
 4x − 3(−8x − 9) = −22
 4(8x + 9) − 3y = −22
 4x − 3(8x + 9) = −22

those are the only options

katecc379 · Answer

so confused

katecc379 · Answer

@welshfella

welshfella · Answer

ok well those are the equations after you've plugged in y = 8x + 9

welshfella · Answer

- you plug it into the second equation

welshfella · Answer

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