85 * 0.20 = 17
85 - 17 = $68
He paid $68 for the jacket
A quadratic equation is set up in the form of ax² + bx +c
First set equation = to 0
0= x² - 5x - 24
Next plug into quadratic formula( -b Plus or minus the √b²-4ac) ÷ 2a
[10 plus or minus √(25² - 4×1×24)] ÷ 2
Solve for inner parenthesis first
√625- 96 = √529
Now set up two equations
(10 + √529) ÷2 = x = 16.5
(10 - √529) ÷2 = x = -6.5
So therefore x = 16.5 and -6.5
No the signs stay the same
They can help you find a common denominator by the bottoms of each fraction if the top ones don't have the same denominator.
