equation 1 : .5x - 2y = 17
equation 2 : 2x + y = 104
using equation 2 find the value for y
2x + y = 104 (subtract 2x on both sides)
y = 104 -2x ( use this value for equation 1)
equation 1 : .5x - 2y = 17
.5x - 2 (104 - 2x) = 17
.5x - 208 + 4x = 17 ( combine the numbers with thesame variable)
4.5x - 208 = 17 ( add 208 on both sides)
4.5x = 17 + 208
4.5x = 225 (divide both side by 4.5)
x = 50 (use this value of x in equation either equation 1 or 2 to find the value of y)
equation 1 : .5x - 2y = 17
.5 (50) - 2y = 17
25 - 2y = 17 (subtract 25 on both sides)
-2y = -8 (divide both by -2)
y = 4
OR equation 2 : 2x + y = 104
2(50) + y = 104
100 + y = 104 (subtract 100 on both sides)
y = 4
therefore x = 50 and y = -4