Question

error analysis a student solved the equation $4x + 12 = 20$ using algebra tiles. he incorrectly says the solution is 8. solve the equation. what mistake might the student have made?
the solution is $square$.
(type the value of x.)

Explanation:

Step1: Isolate the x-term

Subtract 12 from both sides.
$4x + 12 - 12 = 20 - 12$
$4x = 8$

Step2: Solve for x

Divide both sides by 4.
$\frac{4x}{4} = \frac{8}{4}$
$x = 2$

Step3: Identify student's mistake

The student likely added 12 to 20 first, then divided by 4: $\frac{20+12}{4}=8$, instead of subtracting 12 first.

Answer:

The correct solution is $x=2$. The student's mistake was adding 12 to 20 instead of subtracting 12 from 20 before solving for $x$.