A= 1/4E
B= 4E
C= E-4
D= E+4
A+B+C+D=100
25/4E=100
hence, E=16
In order to solve this we'll start by assigning variables to hamburgers and cheeseburgers, since these are what we're trying to find. Lets say x = hamburgers and y = cheeseburgers. So we know two things, we know that x+y= 763 (hamburgers plus cheeseburgers sold equals 763, and we know that y= x+63 (cheeseburgers sold equals 63 more than hamburgers sold). Now we have a system of equations. This can be solved most easily by rearranging each equation to each y, and then set them equal to each other:
x+y=763 -> y=763-x, and we already have y=x+63. Set them equal to each other:
x+63 = 763-x (add x to both sides) -> 2x+63 = 763 (subtract 63 from both sides) -> 2x = 700 (divide both sides by 2) x = 350. So we solved for x, which is hamburgers sold, which is what the question asks for, so your answer is 350 hamburgers were sold on Saturday
x > -1
-2x+5 < 7
-2x<2
Now since you divide by (-1) to get positive 2,you need to flip the sign
(-2)/(-1)= 2 2/(-1)=-2
SO
2x>-2
x > -1
To check the solution do not replace the x by -1 because it shouls be more than -1 (You can choose 0,1,2,3....)
Example choose x=3
-2x3+5<7
-6+5<7
-1<7
C
because it is the only logical answer
