The sum of 8 times a number and 7 is 4.
use the variable b for the unknown number.

Step-by-step 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

d. 145*2 is 290 than the total angle is 360 then minus 290 then divide by two