The number of gallons that will make 12% alcohol is 9*3000 (15*12)= 150 gallons
Step-by-step explanation:
lets separate z from each equation
2z=x-2y-2
4z=5x+2y+2
5z=-5y
so
z=x/2-y-1
z=5x/4+y/2+1/2
z=-y
lets use the first and third equation
we have z=-y we replace this z at the first equation
-y=x/2-y-1 so x/2-1=0
x/2=1
x=2
now we replace z=-y and x=2 at the second equation so
-y=5*2/4+y/2+1/2
-y/2-y=5/2+1/2
-3y/2=6/2
-3y/2=3
-y/2=1
y=-2
we know that z=-y
so z =-(-2)=2
finaly we have that
x=2 ,y=-2 ,z=2
When solving for x when x is squared, you need to isolate the variable that is squared in one side and have the rest of the terms on the other side then find the squared root of both sides of the equation