A. 6x-y=1 can go to 6x-y-1=0 and then 6x-1 = y
Answer:

I inserted an image of the equation.
Step-by-step explanation:
Hope this helps!
3 tons + 600 lbs = 6600 lbs
14/100 = 0.14
0.14x72 = 10.08
3j+2t=14 subtract 2t from both sides
3j=14-2t divide both sides by 3
j=(14-2t)/3
...
5j+6t=28, using j found above in this equation yields.
5(14-2t)/3+6t=28 perform indicated multiplication on left side
(70-10t+18t)/3=28 multiply both sides by 3
70-10t+18t=84 combine like terms on the left side
70+8t=84 subtract 70 from both sides
8t=14 divide both sides by 8
t=$1.75, and since j=(14-2t)/3
j=(14-2(1.75))/3
j=$3.50
So a pound of trail mix costs $1.75 and a pound of jelly beans costs $3.50.