Question

# Solve 5x2−6x−2=0

A
x=35±1925
B
x=25±195
C
x=35±195
D
x=35±175

Solution

## The correct option is C x=35±√195In the equation, 5x2−6x−2=0 a = 5, b = -6 and c= -2. Divide by 5 to reduce it to standard form.   5x2−6x−25=0 x2−65x−25=0 Add and subtract (35)2 to complete the squares, x2−65x−25+(35)2−(35)2=0 x2−2×x×35x+(35)2−(35)2−25=0 (x−35)2−(35)2−25=0 On completing the squares,  (x−35)2=1925 Taking square root on both sides, (x−35)=±√195 Thus, the roots of 5x2−6x−2=0 are x=35±√195

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