An expression is evaluated as shown below. 8 + 3 × (4 ÷ 2) − 7

Step 1: 8 + 3 × 2 − 7

Step 2: 11 × 2 − 7

Step 3: 22 − 7

Step 4: 15

In which step does a mistake first appear?

1. 2. ∠b and ∠y are right angles. 3.? 4.? which two statements are missing in steps 3 and 4? ∠x ≅ ∠c △abc ~ △zyx by the sas similarity theorem. ∠b ≅ ∠y △abc ~ △zyx by the sas similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem.