Question 262535
ned help on algebra involving substitution x=y+4
-x+2y=7 

1.) x = y + 4
2.) -x + 2y = 7

Substitute y + 4 for x from equation 1.) in equation 2.):

-(y + 4) + 2y = 7
-y - 4 + 2y = 7

Solve the above for y then calculate x from 1.) as y + 4