Question

The work of a student to solve a set of equations is shown below:

Equation 1: x + 2y = 10
Equation 2: 2x + 5y = 15

Step 1: −2(x + 2y) = −2(10)
2x + 5y = 15

Step 2: −2x − 4y = −10
2x + 5y = 15

Step 3: 1y = 5

Step 4: x + 2(1) = 10

Step 5: x = 8
In which step did the student first make an error? (4 points)


Step 1

Step 2

Step 3

Step 4

Answer 1

The student first made an error in Step 3. The correct solution should have been y = 2.