Answer:

Explanation:
The original equation is
-7x + y = -17
To solve for y in terms of x, add 7x to both sides which is what the diagram is showing
-7x + y + 7x = -17 + 7x
-7x and +7x on the left side cancel giving
y = -17 + 7x
which can be re-written using the given boxes as
