Solve -2*(2x+8)^2-15=

$$- 2 \cdot ( 2 x + 8 ) ^ { 2 } - 15 =$$

Evaluate

$$-8\left(x+4\right)^{2}-15$$

Solution Steps

Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(2x+8\right)^{2}.

$$-2\left(4x^{2}+32x+64\right)-15$$

Use the distributive property to multiply -2 by 4x^{2}+32x+64.

$$-8x^{2}-64x-128-15$$

Subtract 15 from -128 to get -143.

$$-8x^{2}-64x-143$$

Expand

$$-8x^{2}-64x-143$$

Solution Steps

Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(2x+8\right)^{2}.

$$-2\left(4x^{2}+32x+64\right)-15$$

Use the distributive property to multiply -2 by 4x^{2}+32x+64.

$$-8x^{2}-64x-128-15$$

Subtract 15 from -128 to get -143.

$$-8x^{2}-64x-143$$