Question

A number added to its square gives 56. The number is:

• A. 12
• B. 9
• C. 8
• D. 7

Answer 1

The correct option is D 7

Given that,

A number added to its square gives $56$.

To find out,

The number.

Let the number be $x$.
Hence, $x^2+x=56$
$\Rightarrow x^2+x-56=0$

$\Rightarrow x^2+8x-7x-56=0$

$\Rightarrow x(x+8)-7(x+8)=0$
$\Rightarrow (x+8)(x-7)=0$
Hence, $x=-8$ or $x=7$

Given options have only $7$. Hence, option D is correct.