If I had to guess that it mean -4x + 6y = -18 and y = -2x+21:
Since we have a y =, we can plug that in.
-4x + 6(-2x + 21) = -18
-4x -12x + 126 = -18
-16x = -18 -126
-16x = -144
-16x/-16 = -144/-16
x = 9
The value of x is equal to 9 and the value of y is equal to 3
Data given;
To solve the linear equations above, we have to use substitution method.
from equation 1
[tex]-4x + 6y = -18[/tex]
Make x the subject of formula
[tex]-4x + 6y = -18\\x = \frac{9 + 3y}{2}[/tex][tex]-4x + 6y = -18\\-4x = -18 - 6y \\\frac{-4x}{-4} = \frac{-18-6y}{-4}\\ x = \frac{9 + 3y}{2}[/tex]
substitute the value of x into equation 2
[tex]y = -2x + 21\\y = -2(\frac{9+3y}{2})+ 21\\ y = {-9-3y} + 21\\y = -3y + 12\\4y = 12\\4y/4 = 12/4\\y = 3[/tex]
substitute the value of y into either equation 1 or 2
[tex]y = -2x + 21\\3 = -2x + 21\\2x = 21 - 3\\2x = 18\\2x/2 = 18/2\\x = 9[/tex]
From the calculations above, the value of x is 9 and y is 3
Learn more on system of equations here;
https://brainly.com/question/13729904
