Answer:
504 combos
Step-by-step explanation:
Cannot use digits twice and last is '7'
9 digits for first place choice
8 digits for second place
7 digits for third place
only '7' for fourth place 9 x 8 x7 = 504 combos
Answer:
C choice.
Step-by-step explanation:

First, we move the same terms to the same side.

Then we move 6 to divide - 18.

Answer:
(-2, -4.5)
Step-by-step explanation:
We can solve this equation with substitution.
x=2y+7
3x-2y=3
We can "substitute" 2y+7 for x into the second equation:
3(2y+7)-2y=3
Distribute the 3
6y+21-2y=3
Add like terms
4y+21=3
Subtract 21 from both sides
4y=-18
Divide both sides by 4 to isolate y
y=-4.5
Plug -4.5 back in for y:
x=2(-4.5)+7
x=-9+7
x=-2
(x,y)=(-2,-4.5)
Answer:
Joseph has 175
Molly has 275
Step-by-step explanation:
y = 15x + 25
y = 25x + 25
You can put this into Desmos
Red is Joseph and Molly is blue
Molly - (10, 275)
Joseph - (10, 175)
x = the time
y = money over time