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The roots of the quadratic equation 2x2x^2x2​-x-3=0 are:
Question

The roots of the quadratic equation 2x2x^2​-x-3=0 are:

A.

1,-32\frac{3}{2}​​

B.

-1,32\frac{3}{2}

C.

1, 32\frac{3}{2}

D.

-1,-32\frac{3}{2}

Correct option is B

Given: 

2x2x3=0 2x^2-x-3=0 

Formula used:

Discrimanant (D) = b24acb^2 - 4ac​​

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}​​

Solution:

Here : a=1,b=1,c=3a=1 , b = -1, c= -3 

D = b24acb^2 - 4ac  = (1)24(2)(3)=1+24=25(−1) 2 −4(2)(−3)=1+24=25

Substitute the value in above formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = (1)±252(2)=1±54 \frac{-(-1) \pm \sqrt{25}}{2(2)} = \frac{1 \pm 5}{4} 

Solve the root:

x1=1+54=64=32x_1 = \frac{1 + 5}{4} = \frac{6}{4} = \frac{3}{2} 

x2=154=44=1x_2 = \frac{1 - 5}{4} = \frac{-4}{4} = -1 

So the root of quadratic equation is  32,1\frac{3}{2}, -1

Thus the correct answer is (B) 

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