A student attempted to check whether x=4 satisfies the equation 9x−4=5x+12 and wrote the following steps:
LHS =9(4)−4=36−4=32
RHS =5(4)+12=20+12=22
Therefore 32=22, so x=4 is a solution.
a. (i) Locate and clearly state the mathematical error in the student’s working.
b. (ii) Perform the verification again, correctly, to decide whether x=4 is a solution of the given equation.
c. (iii) Solve the equation 9x−4=5x+12 to obtain the actual solution. Verify your answer.