2c -7 >= 9
2c >= 16
c >= 8
5d + 7 <= 32
5d <= 25
d <= 5
normal arthematic except diving over -1 or flipping (taking inverse -1) flips the operator
Sand to cement
7:3
210:x
ask yourself what number is needed to multiply by 7 to get 210 ( so you'd divide 210 by 7 which is 30). Multiply the other side by thirty as well to get the value of x
3*30 which is 90
2 + 1 = 3
3 - 3 = 0
Hope this helped :)