Question

Solve -5(x-7)^2+30=-20

Answer 1

x=7−√10 or x=7+√10

Explanation:

−5(x−7)2+30=−20

Step 1: Simplify both sides of the equation.

−5x2+70x−215=−20

Step 2: Subtract -20 from both sides.

−5x2+70x−215−(−20)=−20−(−20)

−5x2+70x−195=0

For this equation: a=-5, b=70, c=-195

−5x2+70x+−195=0

Step 3: Use quadratic formula with a=-5, b=70, c=-195.

x=

−b±√b2−4ac

2a

x=

−(70)±√(70)2−4(−5)(−195)

2(−5)

x=

−70±√1000

−10

x=7−√10 or x=7+√10