Find the Roots (Zeros) f(x)=x^2+7x-18

$f (x) = x^{2} + 7 x - 18$

Step 1

Set $x^{2} + 7 x - 18$ equal to $0$ .

$x^{2} + 7 x - 18 = 0$

Step 2

Solve for $x$ .

Factor $x^{2} + 7 x - 18$ using the AC method.

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 18$ and whose sum is $7$ .

$- 2, 9$

Write the factored form using these integers.

$(x - 2) (x + 9) = 0$

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

$x - 2 = 0$

$x + 9 = 0$

Set $x - 2$ equal to $0$ and solve for $x$ .

Set $x - 2$ equal to $0$ .

$x - 2 = 0$

Add $2$ to both sides of the equation.

$x = 2$

Set $x + 9$ equal to $0$ and solve for $x$ .

Set $x + 9$ equal to $0$ .

$x + 9 = 0$

Subtract $9$ from both sides of the equation.

$x = - 9$

The final solution is all the values that make $(x - 2) (x + 9) = 0$ true.

$x = 2, - 9$

Step 3

Find the Roots (Zeros) f(x)=x^2+7x-18

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