from the first: y = 9000-x , you had it backwards
so .06x + .15(9000-x) = 1215
.06x + 1350 - .15x = 1215
-.09x = -135
x = 1500
then y = 9000-1500 = 7500
You also lost the equal sign in your last 2 lines
solve the system by substitution
x+y=9000
.06x+.15y=1215
.06x+.15(x-9000)=1215
.06x+.15x-1350=1215
.21x-1350=1215
x-1350+1214.79
x+2564.79
don't look right? where did I go wrong
1 answer
2 answers