It is 4170 I believe if my calculations are correct
Answer:
5x+17
Step-by-step explanation:
2(x+7) + 3(x+1)
- Distribute(Expand) -> 2x+14 + 3x+3
- Simplify by combining like terms -> 5x+17
Answer: 15
Step-by-step explanation: Use the formula: 
Remember
should always be the hypotenuse or the longest side.
---> evaluate the exponents
----> subtract 12544 to the other side
---> take the square root of both sides

Answer: (-2;8)

Step-by-step explanation:
Answer:
There area 14 one cent stamps
Step-by-step explanation:
Let
x -----> the number of 1 cent stamps
y -----> the number of 8 cent stamps
z -----> the number of 12 cent stamps
we know that
0.01x+0.08y+0.12z=1.78 -------> equation A
x=y+4 ------> y=x-4 -----> equation B
x=2z -----> z=0.5x ------> equation C
substitute equation B and equation C in equation A and solve for x
0.01x+0.08(x-4)+0.12(0.5x)=1.78
0.01x+0.08x-0.32+0.06x=1.78
0.15x=1.78 +0.32
0.15x=2.10
x=14
therefore
There area 14 one cent stamps