Answer:

Explanation:
First your'e going to want to make an equation for this.
Sum (addition) of 8 times a number (they say to use b) and 7 is 4 (The answer)
The equation is going to look like this 8b + 7 = 4
now we can start to solve this.
Subtract 7 over and get: 8b = -3
Divide both sides by 8 and get b =

You can test this by putting it back into the equation 8(-3/8) = -3
-3+7 = 4