Question

Which equation is equivalent to square root x2+81=x+10?

A. x + 9 = x + 10
B. x + 9 = x2 + 20x + 100
C. x2 + 81 = x2 + 100
D. x2 + 81 = x2 + 20x + 100

Answer 1

D is the right answer

Answer 2

Option D is correct

`x^2+81 = x62+20x+100`

Explanation:

Given the equation:

`√(x^2+81)=x+10`

Squaring both sides we get;

`x^2+81 = (x+10)^2`

Using identity rule:

`(a+b)^2 = a^2+2ab+b^2`

then;

`x^2+81 = x62+20x+100`

Therefore,
`x^2+81 = x62+20x+100` equation is equivalent to
`√(x^2+81)=x+10`