To solve this, I'm assuming that the equations both represent angles:
There is a theorem that states that an exterior angle of a triangle is equivalent to the sum of two remote triangles. Knowing this:
11x + 7 = 7x + 14 + 25
11x + 7 = 7x + 39
4x = 32
x = 8
I would say, it is round, and flat on two sides, like a can, pipe, straw, unsharpened pencil, or a piece of your leg.
A:amount of money invested in the account with 3% simple interest
B: amount of money invested in the account with 4.5% simple interest
a+b=25000 ——>a=25000-b
0.03a+0.045b=900
30a+45b=900000
2a+3b=60000
2(25000-b)+3b=60000
50000-2b+3b=60000
B=10000
A=25000-10000=15000