Question

Answer and if you can put an explanation that would ben nice.
Explanation not necessary

Answer 1

a

Explanation:

if you substitute for example in the first 2 boxes you have -1 for x and 5 for y so substitute these in for x and y so 5=2(-1)+7. Next do 2 time -1 = -2 the add 7. -2+7=5 so 5=5 hope this helps