Let S be the sum,
S = 2 + 4 + 6 + ... + 2 (n - 2) + 2 (n - 1) + 2n
Reverse the order of terms:
S = 2n + 2 (n - 1) + 2 (n - 2) + ... + 6 + 4 + 2
Add up terms in the same positions, so that twice the sum is
2S = (2n + 2) + (2n + 2) + (2n + 2) + ... + (2n + 2)
or
2S = n (2n + 2)
Divide both sides by 2 to solve for S :
S = n (n + 1)
Answer:
the answer would be 20
Step-by-step explanation:
so if 18-(-2)=?
two nwgatives make a positive. So the equation would turn into 18+2=20
Im not 100% if this is right but htis is how I was taught to do it.
13,61,25,19,41
:) hope i could help :)
Answer:
y=-4/-3x+1
Step-by-step explanation:
Answer:
60
Step-by-step explanation:
1. Calculate area of front surface:
Area of rectangle + Area of smaller rectangle
6*3 + 2*1 = 20
2. then multiply the area by the depth (3)
20 * 3 = 60 cm^3
