SAT Mathematics Practice Test 2

The problem asks for the sum of the roots of the quadratic equation $2{\mathit{m}}^2-16\mathit{m}+8=0,$Dividing each side of the equation by 2 gives ${\mathit{m}}^2-8\mathit{m}+4=0$.If the roots of ${\mathit{m}}^2-8\mathit{m}+4=0$ are ${\mathit{s}}_1$ and ${\mathit{s}}_2$ then the equation can be factored as ${\mathit{m}}^2-8\mathit{m}+4=\left(\mathit{m}-{\mathit{s}}_1\right)\left(\mathit{m}-{\mathit{s}}_2\right)$ gives $-8=-{\mathit{s}}_1-{\mathit{s}}_2$, or ${\mathit{s}}_1+{\mathit{s}}_2=8$
Alternatively, one can apply the quadratic formula to either $2{\mathit{m}}^2-16\mathit{m}+8=0$ or ${\mathit{m}}^2-8\mathit{m}+4=0$.The quadratic formula to either $2{\mathit{m}}^2-16\mathit{m}+8=0$ or ${\mathit{m}}^2-8\mathit{m}+4=0$.The quadratic formula gives two solutions ,$4-2\sqrt{3}$ and $4+2\sqrt{3}$ whose sum is 8
Choices A, B, and C are incorrect and may result from calculation errors when applying the quadratic formula or a sign error when determining the sum of the roots of a quadratic equation from its coefficients