How do you solve #sqrt(x^2+8x-9)=x#?

3 Answers
Mar 10, 2018

Answer:

#x=9/8#

Explanation:

#sqrt(x^2+8x-9) = x#

Squaring both sides,
#x^2+8x-9 = x^2#

Subtracting #x^2# from both sides,
#8x-9=0#
#8x=9#
#x=9/8#

Mar 10, 2018

Answer:

#x=9/8#

Explanation:

#color(blue)"square both sides"#

#rArr(sqrt(x^2+8x-9))^2=x^2#

#rArrcancel(x^2)+8x-9=cancel(x^2)#

#rArr8x=9rArrx=9/8#

#color(blue)"As a check"#

#rArrsqrt((9/8)^2+8(9/8)-9)#

#=sqrt(81/64cancel(+9)cancel(-9))=9/8=" right side"#

#rArrx=9/8" is the solution"#

Mar 10, 2018

Answer:

#x=9/8#

Explanation:

We can square both sides of the equation.

#sqrt(x^2+8x-9)=x#

#x^2+8x-9=x^2#

#8x-9=0#

#8x=9#

#x=9/8#