Hi Mike

For question 13 test 1 no calculator, I used plugging in. I made x = 4 and solved to get 42/13. then I plugged 4 into my answer choices and B gave me 42/13.

I am curious as to why you did not use plug in for your answer and explanation.

how can you use plug-in for #13 on page 607?

how would you use substitution to figure out #26 on test 4 page 722?