Solve -8x^2+3+9x^2-6-2x

$$- 8 x ^ { 2 } + 3 + 9 x ^ { 2 } - 6 - 2 x$$

Evaluate

$$\left(x-3\right)\left(x+1\right)$$

Solution Steps

Combine -8x^{2} and 9x^{2} to get x^{2}.

$$x^{2}+3-6-2x$$

Subtract 6 from 3 to get -3.

$$x^{2}-3-2x$$

Factor

$$\left(x-3\right)\left(x+1\right)$$

Solution Steps

Multiply and combine like terms.

$$x^{2}-2x-3$$

Factor the expression by grouping. First, the expression needs to be rewritten as x^{2}+ax+bx-3. To find a and b, set up a system to be solved.

$$a+b=-2 ab=1\left(-3\right)=-3$$

Since ab is negative, a and b have the opposite signs. Since a+b is negative, the negative number has greater absolute value than the positive. The only such pair is the system solution.

$$a=-3 b=1$$

Rewrite x^{2}-2x-3 as \left(x^{2}-3x\right)+\left(x-3\right).

$$\left(x^{2}-3x\right)+\left(x-3\right)$$

Factor out x in x^{2}-3x.

$$x\left(x-3\right)+x-3$$

Factor out common term x-3 by using distributive property.

$$\left(x-3\right)\left(x+1\right)$$