Your answer is 35 because you do 35 divided by 50 which equals 0.7 starting from the decimal, move two spaces to the right and you will get 70%
Their is not a lot of information but I think it is 12*24=288
If Ivan used all 3/4 pound of hamburger, then each patty would be 1/4 pound.
On step 2 you already substituted for y, from there you can solve for x:
7x + 2(3 - 3x) = 1
Multiply 2 into (3 - 3x)
7x + 6 - 6x = 1
Combine like terms
x + 6 = 1
Subtract 6 on both sides
x = -5