Question

If the discriminant of quadratic equation 5x2-px+12=0 is 16,then the value of p is

Answer 1

Answer:

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Step-by-step explanation:

the quadratic equation ax^2+bx+c=0 has equal roots the the discriminant is zero.

i.e. b^2-4ac=0

On comparing the equation,

a=1,b=p,c=16

Substitute the value,

(p)^2-4(1)(16)=0

p^2=64

Taking root both side,

p=\pm 8

The value of p is 8 or -8.

Solution of quadratic equation is x=\frac{-b\pm\sqrt{D}}{2a}

When p=8, x^2+8x+16=0

The solution is,

x=\frac{-(8)\pm\sqrt{0}}{2(1)}

x=\frac{-8}{2}

x=-4

When p=-8, x^2-8x+16=0

The solution is,

x=\frac{-(-8)\pm\sqrt{0}}{2(1)}

x=\frac{8}{2}

x=4

The roots of the equation is 4,-4.