X/-9 + n/-7 = 9
solve for x

9514 1404 393

  x = -(9/7)n -81

Step-by-step explanation:

Subtract the n term.

  x/-9 = 9 -n/-7

Multiply by -9.

  x = -81 -(9/7)n

21.4 i did it already for s1

step-by-step explanation:

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.