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

1 Answer
Jim G.
Nov 11, 2017

#(x,y)to(100,125)#

Explanation:

#"substitute "x=color(red)(4/5y)" into "3x+2y=550#
#"and solve for y"#

#rArr(3xx4/5y)+2y=550#

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

#rArr22/5y=550#

#"multiply both sides by 5"#

#cancel(5)xx22/cancel(5)y=5xx550#

#rArr22y=2750#

#"divide both sides by 22"#

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

#rArry=125#

#"substitute this value into "x=4/5y#

#rArrx=4/5xx125=100#

#color(blue)"As a check"#

#(3xx100)+(2xx125)=300+250=550larr"True"#

#"point of intersection "=(100,125)#

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