Question

Jerry solved this equation: 3 ( x −
1
4
) =
13
6

1. 3x −
3
4
=
13
6

2. 3x −
3
4
+
3
4
=
13
6
+
3
4

3. 3x =
26
12
+
9
12

4. 3x =
35
12

5. (
3
1
)
3
1
x =
35
12
(
3
1
)

6. x =
105
12

In which step did Jerry make an error?
In step 2, he should have subtracted Three-fourths from both sides.
In step 3, he should have found an LCD of 10.
In step 4, he should have subtracted 9 from 26.
In step 5, he should have multiplied both sides by One-third.

Answer 1

Jerry made the error in step 5.

He should have multiplied both sides by 1/3 (the reciprocal of 3), not by 3. From 3x = 35/12, multiplying by 1/3 gives x = (35/12)·(1/3) = 35/36.