How do you solve the system 5x= -25+5y5x=25+5y and 10y=42+2x10y=42+2x?

1 Answer
Jun 13, 2015

Divide the first equation by 55 to get an expression for xx to substitute in the second equation. Solve to find y=4y=4 and hence x=-1x=1

Explanation:

Divide both sides of the first equation by 55 to get:

x = -5+y = y-5x=5+y=y5

Substitute y-5y5 for xx in the second equation:

10y = 42 + 2x = 42 + 2(y - 5)10y=42+2x=42+2(y5)

=42+2y - 10 = 32+2y=42+2y10=32+2y

Subtract 2y2y from both ends to get:

8y = 328y=32

Divide both sides by 88 to get:

y = 4y=4

Then

x = y-5 = 4-5 = -1x=y5=45=1