To find the value of c when d = 3 in the equation c + 2 = 3d + 8, you can substitute the value of d into the equation and then solve for c:
c + 2 = 3(3) + 8
First, calculate 3d:
3d = 3 * 3 = 9
Now, substitute this value into the equation:
c + 2 = 9 + 8
Now, combine like terms on the right side:
c + 2 = 17
To isolate c, subtract 2 from both sides of the equation:
c = 17 - 2
c = 15
So, when d = 3, the value of c is 15.