Question

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)


A)Step 1*i think its this one

B)Step 2

C)Step 3

D)Step 4

Answer 1

B step 2

Explanation:

Answer 2

It is step 2 because the student did not multiply 10 correctly...
They put -10 but 10×(-2) is actually -20.