Use the Quadratic Formula to solve for $y$ . $81 x ^ { 2 } - 90 x y + 25 y ^ { 2 } + 10 y = 0$
A) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } + 8100 x ^ { 2 } } } { 50 }$
B) $y = \frac { 90 x + 10 \pm \sqrt { ( 90 x + 10 ) ^ { 2 } + 8100 x ^ { 2 } } } { 50 }$
C) $y = \frac { 90 x + 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$
D) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$
E) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x + 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$

Question

Use the Quadratic Formula to solve for $y$ .  $81 x ^ { 2 } - 90 x y + 25 y ^ { 2 } + 10 y = 0$ 
A) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } + 8100 x ^ { 2 } } } { 50 }$
B) $y = \frac { 90 x + 10 \pm \sqrt { ( 90 x + 10 ) ^ { 2 } + 8100 x ^ { 2 } } } { 50 }$
C) $y = \frac { 90 x + 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$
D) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x - 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$
E) $y = \frac { 90 x - 10 \pm \sqrt { ( 90 x + 10 ) ^ { 2 } - 8100 x ^ { 2 } } } { 50 }$

Quizplus · Accepted Answer

The quadratic formula is used to solve for $y$ in the form $ay^2 + by + c = 0$. Here, $a = 25$, $b = 10 - 90x$, and $c = 81x^2$. Applying the quadratic formula gives the expression in choice D.

Use the Quadratic Formula to Solve For yyy 81x2−90xy+25y2+10y=081 x ^ { 2 } - 90 x y + 25 y ^ { 2 } + 10 y = 081x2−90xy+25y2+10y=0

Use the Quadratic Formula to Solve For $y$ $81 x ^ { 2 } - 90 x y + 25 y ^ { 2 } + 10 y = 0$