Solve (6x-5+4x^2)+(2x-2)

$$( 6 x - 5 + 4 x ^ { 2 } ) + ( 2 x - 2 )$$

Evaluate

$$4x^{2}+8x-7$$

Solution Steps

Combine 6x and 2x to get 8x.

$$8x-5+4x^{2}-2$$

Subtract 2 from -5 to get -7.

$$8x-7+4x^{2}$$

Factor

$$4\left(x-\left(-\frac{\sqrt{11}}{2}-1\right)\right)\left(x-\left(\frac{\sqrt{11}}{2}-1\right)\right)$$

Steps Using the Quadratic Formula

Combine 6x and 2x to get 8x.

$$factor(8x-5+4x^{2}-2)$$

Subtract 2 from -5 to get -7.

$$factor(8x-7+4x^{2})$$

Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.

$$4x^{2}+8x-7=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$x=\frac{-8±\sqrt{8^{2}-4\times 4\left(-7\right)}}{2\times 4}$$

Square 8.

$$x=\frac{-8±\sqrt{64-4\times 4\left(-7\right)}}{2\times 4}$$

Multiply -4 times 4.

$$x=\frac{-8±\sqrt{64-16\left(-7\right)}}{2\times 4}$$

Multiply -16 times -7.

$$x=\frac{-8±\sqrt{64+112}}{2\times 4}$$

Add 64 to 112.

$$x=\frac{-8±\sqrt{176}}{2\times 4}$$

Take the square root of 176.

$$x=\frac{-8±4\sqrt{11}}{2\times 4}$$

Multiply 2 times 4.

$$x=\frac{-8±4\sqrt{11}}{8}$$

Now solve the equation x=\frac{-8±4\sqrt{11}}{8} when ± is plus. Add -8 to 4\sqrt{11}.

$$x=\frac{4\sqrt{11}-8}{8}$$

Divide -8+4\sqrt{11} by 8.

$$x=\frac{\sqrt{11}}{2}-1$$

Now solve the equation x=\frac{-8±4\sqrt{11}}{8} when ± is minus. Subtract 4\sqrt{11} from -8.

$$x=\frac{-4\sqrt{11}-8}{8}$$

Divide -8-4\sqrt{11} by 8.

$$x=-\frac{\sqrt{11}}{2}-1$$

Factor the original expression using ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right). Substitute -1+\frac{\sqrt{11}}{2} for x_{1} and -1-\frac{\sqrt{11}}{2} for x_{2}.

$$4x^{2}+8x-7=4\left(x-\left(\frac{\sqrt{11}}{2}-1\right)\right)\left(x-\left(-\frac{\sqrt{11}}{2}-1\right)\right)$$