Answer:
Multiplying each side by the denominator
Step-by-step explanation:
3x + 5

7
Subtract 5 to both sides so
3x + 5 - 5

7 - 5
3x

2
Divide 3 to both sides
3x

2

Cancel out the 3 on the left side,

Question 1 Answer: 1cm= 3 feet. I say this because if there is 5 cm on the blueprint, you can do 3 feet for every cm and get 15 feet.
Question 2 Answer: 1 in=1.5 feet. 6÷4= 1.5 therefore the scale factor is 1.5
I can't quite see the other answers if you could zoom in i could answer those as well.