Question

if square of number is added to 3 times the number the sum is 28 find number​

Answer 1

Solution: Let's the number be x

By the first condition,

Square of number+ 3

times of number = 28

i.e

x²+3x= 28

x² +3x - 28= 0..........(1)

x² +7x - 4x- 28=0.....solving

by factorisation

x( x+7)- 4 ( x+ 7)=0

(x- 4) ( x+ 7) = 0

(x- 4)=0 or (x + 7)= 0

x = 4 or x = (-7)

Answer: Number is 4 or (-7)

I hope my answer is correct and help you

Answer 2

Answer:

Required number is -7 or 4

Explanation:

Let the number = x

square of the number = x²

According to the problem given,

square of number is added to 3 times the number the sum is 28

x²+3x = 28

=> x²+3x-28=0

Splitting the middle term,we get

=> x²+7x-4x-28=0

=> x(x+7)-4(x+7)=0

=> (x+7)(x-4)=0

=> x+7 = 0 or x-4 = 0

=> x = -7 or x = 4

Therefore ,

Required number is -7 or 4

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