Question

Justin wrote the following indirect proof:

Prove: 7 is a factor of 91.

Step 1: Assume that 7 is a factor of 91.
Step 2: 91 divided by 7 is 13.
Step 3: A factor is an integer by which another integer is divisible.
Step 4: Therefore, 7 must be a factor of 91.

Which step in Justin's proof is incorrect?

Step 1

Step 2

Step 3

Step 4 i think it step 4 but i'm not sure

Answer 1

step 1

Answer 2

u sure

Answer 3

with indirect proof, you are suppose to state the opposte of what you are proven

Answer 4

ohh ok u right

Answer 5

so it should start with 7 is not a factor of 91

Answer 6

ohh ok