Question

The roots of which of the following quadratic equations are 2 and -5?

A) x2 + 3x+10 = 0

B) x2- 3x + 10 = 0

C) x? + 3x -10 = 0 D) x2- 3x - 10 = 0​

Answer 1

Answer:

Answer

Quadratic equation ax

2

+bx+c=0 will have two distinct real roots if D>0 or b

2

−4ac>0

Given quadratic euations is x

2

−3x+4=0

Now, D=b

2

−4ac

=(−3)

2

−4(1)(4)(a=1,b=−3,c=4)

⇒D=9−16

⇒D=−7<0

∴D<0

So, the given equation has no real roots.