Answer:
should be 63
Step-by-step explanation:
Th answer is b. 54 mm
9x6= 54
Answer:
Below in bold.
Step-by-step explanation:
First term a1 = 13
11th term a11 = a1 + 10d = 83
So a1 + 10d - a1 = 83 - 13
10d = 70
d = 10
The common difference d = 7.
Sum of n terms = (n/2)[2a1 + (n - 1)d]
Sum of the first 20 terms:
S20 = (20/2)[2*13 + (20-1)7]
S20 = 10 *(26 + 19*7)
S20 = 10*159 = 1590.
1y + 2x = 0 ⇒ -2x - 1y = 0
4x + 1y = 3 ⇒ <u>4x + 1y = 3</u>
<u>2x</u> = <u>3</u>
2 2
x = 1.5
4(1.5) + y = 3
6 + y = 3
<u>- 6 - 6</u>
y = -3
(x, y) = (1.5, -3)