Answer:
BD = 78
x = 7
Step-by-step explanation:
As we can see, BC plus CD will be equal to BD. That means we can set up the equation 6x+15+3x = 10x+8. First, we combine like terms to get 9x+15 = 10x+8. Then we can subtract 9x from both sides, to get 15 = x+8. We then subtract 8 from both sides to get x = 7. Since x = 7, we can plug in x for the equation given for BD, 10(7)+8. This will come out to 78.
