Question 662458
Starting with 
x+y=18
x*y=56
Rearrange one of the equations to solve for one variable
x=18-y
use this in substitution within the other equation
(18-y)y=56
18y - y^2 = 56
Subtract by 18y and y^2 on both sides
0 = 56 - 18y + y^2
Rearranging the quadradic equation
y^2 - 18y +56 = 0
(y-14)(y-4)
y-14=0 so y=14
y-4=0, so y=4
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-Reading Boosters