Ineed writing the 2 equations for systems of equations on #7 #8 and #9

450s+150c=5700 and

450s+300c=7800  so subtracting the 2nd from the first gives you:

-150c=-2100

c=$14.00  and since 450s+300c=7800

450s+14(300)=7800

450s=3600

s=$8.00

So senior tickets are $8.00 and children's tickets are $14.00



A=40+10L, B=30+12L

A=B when

40+10L=30+12L

-2L=-10

L=5

So A and B will cost the same when purchasing five lines.

The cost for 5 lines is:

30+12L=30+60=90

So five lines cost $90 under either plan.

If you needed four lines:

A=40+40=80, B=30+48=78

So if you only need four lines B is cheaper at $78, $2 less than A.



11(3S+14L=203) and -3(11S+11L=220) gives you:

33S+154L=2233 and -33S-33L=-660  adding these two together yields:

121L=1573

L=$13.00 which makes 3S+14L=203 become

3S+14(13)=203

3S+182=203

3S=21

S=$7.00

So a small box costs $7.00 and a large box costs $13.00