Opening Problem A farmer has plant
at certain trees
a piece of land. The land is in the form of an
Isosceres triangular region with base 100m
and height 50m. The trees are grown up In different rows In each row the
distance bin two adjacent trees is 5m. The
distance between
consecutive rows is
5m too.
How many rows are there on a piece of land? ​

The correct answer is $90

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.