21/4 is equivalent to...
4 x 5 = 20
so, 21/4 = 5 1/4
5 1/4 = 5.25
5 1/4 = 5 2/8 = 42/8
42/8 = 84/16
<span>X+3y=10
X-5y=-2
--------------subtract
8y = 12
y = 12/8 = 3/2 = 1.5
</span><span>X+3y=10
x = 10 - 3y
x = 10 - 3(1.5)
x = 10 - 4.5
x = 5.5
answer
x = 5.5 and y = 1.5 </span>