How do you solve sqrt(8x+1)=x+2?

1 Answer
Mar 25, 2018

x=1" or "x=3

Explanation:

color(blue)"square both sides"

(sqrt(8x+1))^2=(x+2)^2

rArr8x+1=x^2+4x+4

"rearrange into "color(blue)"standard form"

rArrx^2-4x+3=0

"The factors of + 3 which sum to - 4 are - 1 and - 3"

rArr(x-1)(x-3)=0

"equate each factor to zero and solve for x"

x-1=0rArrx=1

x-3=0rArrx=3

color(blue)"As a check"

Substitute these values into the equation and if both sides are equal then they are the solutions.

x=1rArrsqrt9=3" and "1+2=3 color(white)(x)✔︎

x=3rArrsqrt25=5" and "3+2=5color(white)(x)✔︎

rArrx=1" or "x=3" are the solutions"