Answer:
15th term = 116
Step-by-step explanation:
a= 4
Sum of an A.P = n/2 {2a + (n-1)d}
sum of first five term is equal to one-fourth of the sum of the next five term
5/2{ 2*4 + (5-1)d} = 1/4 × 10/2{2*4 + (10-1)d
5/2 {8 + 4d} = 1/4 × 5{ 8 + 9d}
40/2 + 20/2d = 1/4{ 40 + 45d)
20 + 10d= 40/4 + 45/4d
20 + 10d = 10 + 45/4d
20 - 10 = 45/4d - 10d
10 =45d - 40d /4
10 = 5/4d
Divide both sides by 5/4
10 ÷5/4 = d
10×4/5 = d
40/5 = d
8 = d
d= 8
Find the 15th term
15th term = a + (n-1)d
= 4 + (15-1)8
= 4 + (14)8
= 4 + 112
= 116
The 15th term is 116
The answer is 90 different pairs.
So if there are 10 topics and each will get 9 pairings , so the over all pairs you will get is 90.
Answer:
Option D. 9
Step-by-step explanation:
There are two ways to obtain the answer to the question.
Method 1:
Let 2x + 1 = 0
Making x the subject, we have
2x + 1 = 0
Collect like terms
2x = –1
Divide both side by 2
x = –1/2
Now, put the value of x into the expression 4x³ – 6x² – 8x + 7, we have:
4x³ – 6x² – 8x + 7
x = –1/2
4(–1/2)³ – 6(–1/2)² – 8(–1/2) + 7
4(–1/8) – 6(1/4) – 8(–1/2) + 7
–1/2 – 3/2 + 4 +7
– 4/2 + 4 + 7
– 2 + 4 + 7
= 9
Method 2:
Divide 4x³ – 6x² – 8x + 7 by 2x + 1
Please see attached photo for explanation.