Question

. A student solving the absolute value equation (5x= x + 12 correctly determined that x =-2 or 3. When the solutions are checked in the equation, (A) both solutions are verified. (B) - 2 must be disregarded as an extraneous root. (C) 3 must be disregarded as an extraneous root. (D) both solutions must be disregarded as extraneous roots.

Answer 1

negative 2 must be disregarded

plug in -2 into both x's

5x=x +12

5(-2)=(-2) +12

dustribute

-10= -2 + 12

-10 = 10

this is not correct

plug in 3 to both x's

5x= x+12

5(3)= (3) +12

15= 3+ 12

15 =15

this is correct