Solve 2x^2+10x-12geq0

$$2 x ^ { 2 } + 10 x - 12 \geq 0$$

Solve for x

$$x\in (-\infty,-6]\cup [1,\infty)$$

Steps Using the Quadratic Formula

To solve the inequality, factor the left hand side. 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.

$$2x^{2}+10x-12=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 2 for a, 10 for b, and -12 for c in the quadratic formula.

$$x=\frac{-10±\sqrt{10^{2}-4\times 2\left(-12\right)}}{2\times 2}$$

Do the calculations.

$$x=\frac{-10±14}{4}$$

Solve the equation x=\frac{-10±14}{4} when ± is plus and when ± is minus.

$$x=1 x=-6$$

Rewrite the inequality by using the obtained solutions.

$$2\left(x-1\right)\left(x+6\right)\geq 0$$

For the product to be ≥0, x-1 and x+6 have to be both ≤0 or both ≥0. Consider the case when x-1 and x+6 are both ≤0.

$$x-1\leq 0 x+6\leq 0$$

The solution satisfying both inequalities is x\leq -6.

$$x\leq -6$$

Consider the case when x-1 and x+6 are both ≥0.

$$x+6\geq 0 x-1\geq 0$$

The solution satisfying both inequalities is x\geq 1.

$$x\geq 1$$

The final solution is the union of the obtained solutions.

$$x\leq -6\text{; }x\geq 1$$