Solve x^2-5x-36 - ScanMath

Question

Factor the expression

(x - 9) (x + 4)

Evaluate

x^{2} - 5 x - 36

Rewrite the expression

x^{2} + (4 - 9) x - 36

Calculate

x^{2} + 4 x - 9 x - 36

Rewrite the expression

x \times x + x \times 4 - 9 x - 9 \times 4

Factor out x from the expression

x (x + 4) - 9 x - 9 \times 4

Factor out - 9 from the expression

x (x + 4) - 9 (x + 4)

Solution

(x - 9) (x + 4)

Show Solution

x_{1} = - 4, x_{2} = 9

Evaluate

x^{2} - 5 x - 36

To find the roots of the expression,set the expression equal to 0

x^{2} - 5 x - 36 = 0

Factor the expression

More Steps

Evaluate

x^{2} - 5 x - 36

Rewrite the expression

x^{2} + (4 - 9) x - 36

Calculate

x^{2} + 4 x - 9 x - 36

Rewrite the expression

x \times x + x \times 4 - 9 x - 9 \times 4

Factor out x from the expression

x (x + 4) - 9 x - 9 \times 4

Factor out - 9 from the expression

x (x + 4) - 9 (x + 4)

Factor out x + 4 from the expression

(x - 9) (x + 4)

(x - 9) (x + 4) = 0

When the product of factors equals 0,at least one factor is 0

x - 9 = 0 x + 4 = 0

Solve the equation for x

More Steps

Evaluate

x - 9 = 0

Move the constant to the right-hand side and change its sign

x = 0 + 9

Removing 0 doesn't change the value,so remove it from the expression

x = 9

x = 9 x + 4 = 0

Solve the equation for x

More Steps

Evaluate

x + 4 = 0

Move the constant to the right-hand side and change its sign

x = 0 - 4

Removing 0 doesn't change the value,so remove it from the expression

x = - 4

x = 9 x = - 4

Solution

x_{1} = - 4, x_{2} = 9

Show Solution