She sold 2592 pears. If 2592/3=864 then when the total of pears and apples are added it should equal 3,456
2592+864=3456
Sa=lw+wh+lh.............................
It can be solved using triangle inequality.
7 / (x-3) = 1
(x-3) ((7 / (x-3)) = 1 (x-3) multiply both sides by (x-3), (x-3) on the left is cancelled
7 = x-3
3+7 = x - 3 + 3 add both sides by 3, 3 on the right is cancelled
x = 11