x2+4x-21=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 -21 and whose sum is 4.

-3,7

Write the factored form using these integers.

(x-3)(x+7)=0

(x-3)(x+7)=0

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

x-3=0

x+7=0

Set the first factor equal to 0.

x-3=0

Add 3 to both sides of the equation.

x=3

x=3

Set the next factor equal to 0.

x+7=0

Subtract 7 from both sides of the equation.

x=-7

x=-7

The final solution is all the values that make (x-3)(x+7)=0 true.

x=3,-7

Solve Using the Square Root Property x^2+4x-21=0