Question 553434
<pre>
solve the system of equations using the substitution method
x+z=8
y-z=5
x-y=9

x + z = 8____z = 8 - x ---- eq (i)
y - z = 5 ----- eq (ii)
x - y = 9___x - 9 = y ----- wq (iii)

y - z = 5
x - 9 - (8 - x) = 5 ------ Substituting x - 9 for y, and 8 - x for z in eq (ii)
x - 9 - 8 + x = 5
x + x - 17 = 5
2x = 22
{{{highlight_green(matrix(1,5, x, "=", 22/2, "=", 11))}}}

x - 9 = y
11 - 9 = y ------ Substituting 11 for x in eq (iii)
{{{highlight_green(matrix(1,5, y, "=", 11 - 9, "=", 2))}}}

z = 8 - x
z = 8 - 11 ------ Substituting 11 for x in eq (i)
{{{highlight_green(matrix(1,5, z, "=", 8 - 11, "=", - 3))}}}</pre>