what is the system of equation of:

Question

0.25x+0.15y=2.5
1.25x-1.25y=7.5

Answer 1

Multiply Eq1 by 1.25 and Eq2 by 0.25 and subtract:
0.3125x + 0.1875y = 3.125
0.3125x - 0.3125y = 1.875
Diff. : 0.5Y = 1.25
Y = 2.5

In Eq1, replace y with 2.5:
0.25x + 0.15*2.5 = 2.5
0.25x = 2.5 - 0.375 = 2.125
X = 8.5