Solve (x + 5)(3x - 4)

Question

Simplify the expression

3 x^{2} + 11 x - 20

Evaluate

(x + 5) (3 x - 4)

Apply the distributive property

x \times 3 x - x \times 4 + 5 \times 3 x - 5 \times 4

Multiply the terms

More Steps

Evaluate

x \times 3 x

Use the commutative property to reorder the terms

3 x \times x

Multiply the terms

3 x^{2}

3 x^{2} - x \times 4 + 5 \times 3 x - 5 \times 4

Use the commutative property to reorder the terms

3 x^{2} - 4 x + 5 \times 3 x - 5 \times 4

Multiply the numbers

3 x^{2} - 4 x + 15 x - 5 \times 4

Multiply the numbers

3 x^{2} - 4 x + 15 x - 20

Solution

More Steps

Evaluate

- 4 x + 15 x

Collect like terms by calculating the sum or difference of their coefficients

(- 4 + 15) x

Add the numbers

11 x

3 x^{2} + 11 x - 20

Show Solution

x_{1} = - 5, x_{2} = \frac{4}{3}

Alternative Form

x_{1} = - 5, x_{2} = 1. \dot{3}

Evaluate

(x + 5) (3 x - 4)

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

(x + 5) (3 x - 4) = 0

Separate the equation into 2 possible cases

x + 5 = 0 3 x - 4 = 0

Solve the equation

More Steps

Evaluate

x + 5 = 0

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

x = 0 - 5

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

x = - 5

x = - 5 3 x - 4 = 0

Solve the equation

More Steps

Evaluate

3 x - 4 = 0

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

3 x = 0 + 4

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

3 x = 4

Divide both sides

\frac{3 x}{3} = \frac{4}{3}

Divide the numbers

x = \frac{4}{3}

x = - 5 x = \frac{4}{3}

Solution

x_{1} = - 5, x_{2} = \frac{4}{3}

Alternative Form

x_{1} = - 5, x_{2} = 1. \dot{3}

Show Solution