-5x + y = -5.....multiply by -2
-4x + 2y = 2
---------------
10x - 2y = 10 (result of multiplying by -2)
-4x + 2y = 2
-----------------add
6x = 12
x = 12/6
x = 2
-5x + y = -5
-5(2) + y = -5
-10 + y = -5
y = -5 + 10
y = 5
solution is (2,5)
Hmm.. Maybe a situation such as: A sports team lost eight points during their game. How is this presented as an integer?
Increased by 15
past score was x
increased by 15 means he raised to 15+x
it was raised to 83%
therefor
x+15=83
first option is right (and first test was 68%)