1123 will be a good answer
First you take the area,
4 x 2 = 8 cm
Then you take 72 cm and divide it by 8 cm to get your length
So the answer for the length is 9 cm
If asking to simplify 2d + 18
Replace a with 4 and b with -12
3(4) + -12/4 + 4(4) = 16+-12/4+4*4 = 29
