Question 384050
y(9+y)=4(2y+5)
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9y+y^2=8y+20
add -8y to both sides
9y-8y+y^2=8y-8y+20
y+y^2=20
add -20 to both sides
y+y^2-20=20-20
y+y^2-20=0
re organize the terms
y^2+y-20=0
y^2+5y-4y-20=0
y(y+5)-4(y+5)=0
(y-4)(y+5)=0
y= 4 OR y =-5
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