y2-9y+20=0

Consider the form x2+bx+c. Find a pair of integers whose product is c and whose sum is b. In this case, whose product is 20 and whose sum is -9.

-5,-4

Write the factored form using these integers.

(y-5)(y-4)=0

(y-5)(y-4)=0

If any individual factor on the left side of the equation is equal to 0, the entire expression will be equal to 0.

y-5=0

y-4=0

Set the first factor equal to 0.

y-5=0

Add 5 to both sides of the equation.

y=5

y=5

Set the next factor equal to 0.

y-4=0

Add 4 to both sides of the equation.

y=4

y=4

The final solution is all the values that make (y-5)(y-4)=0 true.

y=5,4

Solve for y y^2-9y+20=0