Question

solve: n/42=3/18

Answer 1

n=7

Answer 2

n/20=27/36

Answer 3

cross product : n*18 = 3*42
n = 3*42/18 = 7

Answer 4

same... n*36 = 27*20
n = 27*20/36 = 15

Answer 5

3r + 7 = -20

Answer 6

r=-9

Answer 7

the solution is
3r=-27
r=-9

Answer 8

-4n – 12 = 28

Answer 9

n=-10

Answer 10

-25 = 14 – 3x

Answer 11

x=13