50 big points! me on 5 questions!

1)
Solve using elimination
Multiply the first equation by 2 and the second by 5 so you can figure out x
10x-6y=-18
10x-25y=20
Subtract the two equations
19y=-28
y=-2
Plug y into the equation and you get x=-3
(-3, -2)
2. C Just model the equation 
3. B Again, it's all about turning the word problem into equations
4. D. Use substitution and plug the x into the first equation.
5. 
Multiply the whole first equation by 2.
You can see that because 4*2=8
8x+10y=16
Hope this helps. 

Coinciedent equations are the same equations but indifferent forms
example
2x+3y=2 is coincident with 4x+6=4 (multilied by 2)

so we have
4x+5y=8
next one was have
8x
we see that 4 times 2=8 so we just double the numbers
5 times 2=10
8 times 2=16
answer is 8x+10y=16
missing numbers are 10 and 16

subsitution meathod
absicalyy since you have x=y+2, then subsitue y+2 for x in the equaiton x+y=6 so
(y+2)+y=6
there fro the answer is D

d=desmond
g=george

d is 3 less than g
d=-3+g
d=g-3
combinded scores equals 187
d+g=187

the equations are
d=g-3 and d+g=187
the answer is B

child tikcet is 2 dollars so number of children times cost per child=cost
c times 2=cost=2c

adult tickets are same but differenc cost
6 times a=6a

so number of adults+number of kids=total number of people
c+a=38

cost of adults+cost of kids=total cost
2c+6a=148

the equations are
c+a=38 and 2c+6a=148
the answer is A

the solution is in the form (x,y)
so solv for x and y
5x-3y=-9
2x-5y=4
multily the first equation by -2 and the second equaiton by 5

-10x+6y=18
10x-25y=20
add them together

-10x+6y=18
10x-25y=20  +
0x-19y=38
-19y=38
divide both sides by -19
y=-2
subsitute
5x-3y=-9
5x-3(-2)=-9
5x+6=-9
subtract 6 from both sides
5x=-15
dvide by 5
x=-3

x=-3
y=-2
solution is
(-3,-2)

ANSWERS
missing numbers are 10 and 16
D
B
A
(-3,-2)

Idrk but i think u should figure out the n dia n then the units it will make it way more easier