Question

# If a and b are the roots of the equation $$\displaystyle x^{2}-1=0$$ the form of quadratic equation whose roots are 2a and 2b will be-

A
x242=0
B
x2+4=0
C
x24=0
D
x2+42=0

Solution

## The correct option is C $$\displaystyle x^{2}-4=0$$$$\Rightarrow$$  $$a$$ and $$b$$ are roots of the quadratic equation $$x^2-1=0$$So, $$x^2-1=0$$$$\Rightarrow$$  $$x^2=1$$$$\therefore$$  $$x=\pm 1$$Let $$a=+1$$ and $$b=-1$$Then, $$2a=2$$ and $$2b=-2$$The required quadratic equation,$$(x-2a)(x-2b)=0$$$$\Rightarrow$$  $$(x-2)(x+2)=0$$$$\Rightarrow$$  $$x^2+2x-2x-4=0$$$$\therefore$$  $$x^2-4=0$$The required quadratic equation is $$x^2-4=0$$.Mathematics

Suggest Corrections

0

Similar questions
View More

People also searched for
View More