Answer:
A
Step-by-step explanation:
Notice that
13 - 9 = 4
17 - 13 = 4
so it's likely that each pair of consecutive terms in the sum differ by 4. This means the last term, 149, is equal to 9 plus some multiple of 4 :
149 = 9 + 4k
140 = 4k
k = 140/4
k = 35
This tells you there are 35 + 1 = 36 terms in the sum (since the first term is 9 plus 0 times 4, and the last term is 9 plus 35 times 4). Among the given options, only the first choice contains the same amount of terms.
Put another way, we have

but if we make the sum start at k = 1, we need to replace every instance of k with k - 1, and accordingly adjust the upper limit in the sum.


It's D, it's the only one where it has a -6 at the end other than A, but if you look at the A when distributed there isn't a 23x<span />
Answer:
d-2 and d cannot = 8
Step-by-step explanation:
d^2 -10d+16
-----------------------
d-8
Factor the numerator
( d-8)(d-2)
-------------------
d-8
The undefined values occur when the denominator is equal to zero
d-8 = 0
d= 8
This means d cannot equal 8
Now cancel like terms in the equation ( d-8)
This yields d-2
Answer:
a) 137.9°
b) 12.2° (please refer to explanation because I didn't know what to round to)
Step-by-step explanation:
1a) A supplementary angle will equal 180°, so you must subtract 42.1 from 180
180-42.1 = 137.9
1b) A complementary angle will equal 90°, so you need to use the expression given and add an x for the other part of 90°
8x-20+x = 90
9x-20=90
9x=110
x=12.2