Question

if a number is added to twice of its square, the result is 21. find no.​

Answer 1

question_answer Answers(2)

question_answer Answers(2)Let the number be x. Hence, the number is -7 or 6.

Answer 2

$\huge{\mathcal{\boxed{\underline{Question}}}}$

If a number is added to twice of its square, the result is 21. find no.

$\huge{\mathcal{\boxed{\underline{Solution}}}}$

Let the number be x

A.T.Q.

x+2x² = 21

2x²+x-21 = 0

2x²-6x+7x-21 = 0

2x(x-3)+7(x-3) = 0

(x-3)(2x+7) = 0

x = 3,-7/2