How do you solve the system of equations #x+ y = 55# and #40x + 20y = 1500#?

1 Answer
Angie
Nov 30, 2016

#x=20#
#y=35#

Explanation:

First, simplify the #40x+20y=1500# by dividing both sides by 20. The system becomes:

#2x+y=75#
#x+y=55#

Since #x+y=55#, y can be isolated in the equation, making it #y=55-x#.
Because this is a system of equations, both equations are true for the values of x and y, so we can substitute #55-x# in for y in #2x+y=75#.

#2x+55-x=75#

Simplify and solve for x.

#x+55=75#

#x=20#

Now that we know the x-value, it can be plugged into either one of the equations to get the y-value. Here, I used #x+y=55#.

#20+y=55#

#y=35#

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