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Find the range of values of x for which \(2x^{2} + 7x - 15 &...

Find the range of values of x for which 2x2+7x15>0.

A.

x<32 or x>5

B.

x<5 or x>32

C.

32<x<5

D.

5<x<32

Correct answer is B

2x2+7x15>02x23x+10x15>0

x(2x3)+5(2x3)>0

(x+5)(2x3)>0

For their product to be positive, they are either both +ve or -ve.

x+5>0x>5

2x3>02x>3

x>32

Check:

x>5:x=3

2(3)2+7(3)15=182115=18<0 (Not satisfied)

x > \frac{3}{2}: x = 2

2(2^{2}) + 7(2) - 15 = 8 + 14 - 15 = 7 > 0 (Satisfied)