Solve 4-7x-2x^2 - ScanMath

Question

Factor the expression

(4 + x) (1 - 2 x)

Evaluate

4 - 7 x - 2 x^{2}

Rewrite the expression

4 + (- 8 + 1) x - 2 x^{2}

Calculate

4 - 8 x + x - 2 x^{2}

Rewrite the expression

4 - 4 \times 2 x + x - x \times 2 x

Factor out 4 from the expression

4 (1 - 2 x) + x - x \times 2 x

Factor out x from the expression

4 (1 - 2 x) + x (1 - 2 x)

Solution

(4 + x) (1 - 2 x)

Show Solution

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

Alternative Form

x_{1} = - 4, x_{2} = 0.5

Evaluate

4 - 7 x - 2 x^{2}

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

4 - 7 x - 2 x^{2} = 0

Factor the expression

More Steps

Evaluate

4 - 7 x - 2 x^{2}

Rewrite the expression

4 + (- 8 + 1) x - 2 x^{2}

Calculate

4 - 8 x + x - 2 x^{2}

Rewrite the expression

4 - 4 \times 2 x + x - x \times 2 x

Factor out 4 from the expression

4 (1 - 2 x) + x - x \times 2 x

Factor out x from the expression

4 (1 - 2 x) + x (1 - 2 x)

Factor out 1 - 2 x from the expression

(4 + x) (1 - 2 x)

(4 + x) (1 - 2 x) = 0

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

4 + x = 0 1 - 2 x = 0

Solve the equation for x

More Steps

Evaluate

4 + x = 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 = - 4 1 - 2 x = 0

Solve the equation for x

More Steps

Evaluate

1 - 2 x = 0

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

- 2 x = 0 - 1

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

- 2 x = - 1

Change the signs on both sides of the equation

2 x = 1

Divide both sides

\frac{2 x}{2} = \frac{1}{2}

Divide the numbers

x = \frac{1}{2}

x = - 4 x = \frac{1}{2}

Solution

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

Alternative Form

x_{1} = - 4, x_{2} = 0.5

Show Solution