How do you solve the system of equations #-7x + 5y = - 21# and #- x + y = - 5#?

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Answer 1 · 2018-04-11T20:37:09

The solution is #x = -2# and #y = -7#.

I will show you how to solve this problem using the substitution method.

From the second equation we can write:

# y = x - 5#

And then we plug #y# into the first equation:

#-7x +5*(x - 5) = -21#

#-7x + 5x -25 = -21#

#-2x = 4#

#x = -2#

At the end we solve #y = x - 5#:

#y = -2 - 5#

#y= -7#