How do you solve the system of equations #3x + 2y = 550# and #x = \frac { 4} { 5} y#?

1 Answer
Jim G.
Nov 11, 2016

#x=100" and " y=125#

Explanation:

Substitute #x=4/5y" into " 3x+2y=550#

#rArr3xx4/5y+2y=550#

#rArr12/5y+2y=550#

#rArr12/5y+((2xx5)/(1xx5))y=550#

#rArr12/5y+10/5y=550#

#rArr22/5y=550#

multiply both sides of the equation by 5.

#cancel(5)^1xx(22y)/cancel(5)^1=5xx550=2750#

#rArr22y=2750#

To solve for y, divide both sides by 22.

#(cancel(22) y)/cancel(22)=2750/22rArry=125#

substitute #y=125" into " x=4/5y" to solve for x"#

#x=4/5xx125=4/cancel(5)^1xxcancel(125)^(25)=4xx25=100#

#rArrx=100" and " y=125" is the solution"#

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