SAT Mathematics Practice Test 5

Dividing both sides of the quadratic equation $4{\mathit{x}}^2-8\mathit{x}-12=0$ by 4 yields ${\mathit{x}}^2-2\mathit{x}-3=0$ The equation ${\mathit{x}}^2-2\mathit{x}-3=0$ can be factored as $\left(\mathit{x}+1\right)\left(\mathit{x}-3\right)=0.$ This equation is true when $\mathit{x}+1=0$ or $\mathit{x}-3=0.$ Solving for x gives the solutions to the original quadratic equation: $\mathit{x}=-1$ and $\mathit{x}=3$.
Choices A and C are incorrect because −3 is not a solution of . Choice D is incorrect because 1 is not a solution of