Solve using elimination method -7x+5y=-56;-21x-2y=-168
thsi is how i would do it
lets say equation 1 will be -7x + 5y = -56
and equation 2 is -21x - 2y = -168
nothign can cancel out if you llok at the equation so what i would do is multiply equation 1 by a negative 3 that way the -7x becomes a positive 21x to cancel out(but you have to multpliy everything in the equation by -3 not just the -7x)
so you will have;
21x -15y = 168
now add the two equation together
(21x - 15y= 168) + (-21x - 2y=-168)
notice the x and the total on the right side of equal sign cancels leaving you with :
-17y=o y=0 since 0 dvide by anything is still zero now choose any of your original equation and plug in 0 for y and solve for x