Answer:
a₂₁ = 638
Step-by-step explanation:
substitute n = 21 into the explicit formula
a₂₁ = - 2 + 32(21 - 1) = - 2 + 32(20) = - 2 + 640 = 638
Answer: D
Step-by-step explanation:
The pythagorean theorem shows that
.
This shows that the two shaded squares are equal, so D is incorrect.
Answer:
27 and 23
Step-by-step explanation:
We can solve this problem as a system of equations. X is the first number and Y is the second number.
The first equation is x+y = 50 and the second equation is x-y=4
Now we solve the system, using elimination method:
x+y=50
x-y=4
2x = 54
x = 54/2
x = 27
And from any of the equations we can find Y
27 + y = 50
y = 50 - 27
y = 23
Answer C is correct because 2×(4×305) is the same as (2×4)×305 and 2×4=8.
120 because 60 times two is 120 and six times two is twelve