If nC2 = 15, find the value of n
8
7
6
5
Correct answer is C
nC2 = 15
n!(n−3)!2! = 15
n(n−1)(n−2)!(n−2)!2 = 15
n2 - n = 30
n2 - n - 30 = 0
(n - 6)(n + 5) = 0
n = 6 or n = -5
√2 - 1
1 - √2
√2−12
1−√22
Correct answer is A
1√2+1 x √2−1√2−1
= √2−12−1
= √2−11=√2−1
Evaluate tan 75o; leaving the answer in surd form (radicals)
√3+2
√3+1
√3−1
√3−2
Correct answer is D
Tan 75o = Tan (45o + 30o)
= tan45o+tan30o1−tan45otan30o
= √3+1√3−1
RATIONALIZE THE DENOMINATOR
= √3+1√3−1 X √3+1√3+1
= 4+2√33−1
= 2(2+√3)2
= 2 + √3
Solve; P2+k3 = 5 and 2p = k = 6 simultaneously
p = -6, k = -6
p = -6, k = 6
p = 6, k = 6
p = 6, k = -6
Correct answer is C
P2+k3 = 5
3p+2k6 = 5
2p + 3k = 30
- 2p - k = 6
¯4k4=244
k = 6
From 2p - k = 6
2p - 6 = 6
2p2=122
p = 6
-2
-1
1
2
Correct answer is B
8x−2 = 43x
23(x−2) = 22(3x)
2 3x−4 = 26x
2 x−4 = 6x
−4x−4 = 4−4
x = -1