Question

8 times of a number is added to its
square give a result – 15. Then find
the number by using its quadratic
equation.
​

Answer 1

Step-by-step explanation:

let the unknown no. be 'x'

8 times of number is added to its square

= 8x+x^2

the result id -15

:- x^2+8x= -15

by splitting middle term method

x^2+8x+15=0

x^2+5x+3x+15=0

x(x+5)+3(x+5)=0

(x+3)(x+5)=0

x+5=0 , x+3=0

x= -5, x= -3

now putting x= -5 (verification)

x^2+8x= -15

LHS= x^2+8x

(-5)^2+8(-5)= -15

25-40= -15

therefore -15= -15

and same in x= -3

Answer 2

Answer:

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