Solve the equation by using the Quadratic Formula. $u ^ { 2 } - 10 u + 18 = 0$
A) $u = 10 \pm$ $\sqrt { 7 }$
B) $u = 10 \pm$ $\sqrt { 43 }$
C) $u = 5 \pm$ $\sqrt { 7 }$
D) $u = - 10 \pm$ $\sqrt { 43 }$
E) $u = - 5 \pm$ $\sqrt { 7 }$

Question

Solve the equation by using the Quadratic Formula. $u ^ { 2 } - 10 u + 18 = 0$
A) $u = 10 \pm$  $\sqrt { 7 }$
B) $u = 10 \pm$ $\sqrt { 43 }$
C) $u = 5 \pm$ $\sqrt { 7 }$
D) $u = - 10 \pm$ $\sqrt { 43 }$
E) $u = - 5 \pm$  $\sqrt { 7 }$

Quizplus · Accepted Answer

The quadratic formula is $u = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, where $a = 1$, $b = -10$, and $c = 18$. Plugging these values in gives $u = \frac{10 \pm \sqrt{(-10)^2 - 4(1)(18)}}{2(1)} = \frac{10 \pm \sqrt{100 - 72}}{2} = \frac{10 \pm \sqrt{28}}{2} = 5 \pm \sqrt{7}$.

Solve the Equation by Using the Quadratic Formula u2−10u+18=0u ^ { 2 } - 10 u + 18 = 0u2−10u+18=0

Solve the Equation by Using the Quadratic Formula $u ^ { 2 } - 10 u + 18 = 0$