Write it out as a set of equation:
Let x be number of 8 cent stamps, y be 10 cent stamps, and z be 2 cent stamps.
x=y
z=x+y
8x+10y+2z=440
Lets first solve for x:
from x=y and z=2x(from first equation) the last equation is
8x+10x+4x=440
22x=440
x=20
know that x=20, you also know that y=20 as well, since z=x+y, z=40.
So 20 8-cent stamps, 20 10-cent stamps, and 40 2-cent stamps.
Answer:
225
Step-by-step explanation:
3240k = 2×2×2×3×3×3×3×5×k
Every factor should be in groups of 3
(3×5)² = k
k = 225
Combine the terms. Note that: one positive and one negative sign results in a negative sign.
Simplify: 5 + (-4) = 5 - 4 = 1
1 + (-7) = 1 - 7 = -6
-6 + 2 = -4
-4 is your answer
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