5 (c + d) + 2 (4c + 2d)

13c + 9d

first you would distribute so multply 5 to c and d an dthen multply 2 to 4c and 2d

5c+5d=8c+4d

now we can subtract 4d from both sides

5c+d=8c

and subtract 5c from both sides

d=3c this is what your left with so this is your answer