solve using substitution& elimination method 2x/5+3y/4=5;3x/10+5y/8=8
2x/5+3y/4=5
3x/10+5y/8=8
Fractions are usually messy, so let's get rid of them:
8x+15y = 100
12x+25y = 320
For substitution, note that 12x = (3/2)(8x), and since 8x = 100-15y,
(3/2)(100-15y)+25y = 320
Now you can find y, and then x.
For elimination, let's eliminate y, using LCM(15,25)=75:
40x+75y = 500
36x+75y = 960
Now subtract, and you eliminate y:
4x = -460
Now find x, and then y.