15% off means the dvd is selling for 85% of the original price ( 100% - 15%=85%)
Multiply the original price by 85%
12 x 0.85 = 10.20
The price is $10.20
Driving 40 miles in 2 hours is the answer
Step-by-step explanation:

The simplest method is "brute force". Calculate each term and add them up.
∑ = 3(1) + 3(2) + 3(3) + 3(4) + 3(5)
∑ = 3 + 6 + 9 + 12 + 15
∑ = 45

∑ = (2×1)² + (2×2)² + (2×3)² + (2×4)²
∑ = 4 + 16 + 36 + 64
∑ = 120

∑ = (2×3−10) + (2×4−10) + (2×5−10) + (2×6−10)
∑ = -4 + -2 + 0 + 2
∑ = -4
4. 1 + 1/4 + 1/16 + 1/64 + 1/256
This is a geometric sequence where the first term is 1 and the common ratio is 1/4. The nth term is:
a = 1 (1/4)ⁿ⁻¹
So the series is:

5. -5 + -1 + 3 + 7 + 11
This is an arithmetic sequence where the first term is -5 and the common difference is 4. The nth term is:
a = -5 + 4(n−1)
a = -5 + 4n − 4
a = 4n − 9
So the series is:

Answer:
4x+2
Step-by-step explanation:
a= 2x - 3 and b= 2x+5
a+b = 2x-3 + 2x+5
Combine like terms
a+b = 4x+2
Answer:
x = ± 
Step-by-step explanation:
Given
x² = 20 ( take the square root of both sides )
x = ± 
which can be simplified to
x = ± 2
[ ± means plus or minus ]