Make x the subject of the relation 1+ax1−ax = pq
p+qa(p−q)
p−qa(p+q)
p−qapq
pqa(p−q)
Correct answer is B
1+ax1−ax = pq by cross multiplication,
q(1 + ax) = p(1 - ax)
q + qax = p - pax
qax + pax = p - q
∴ x = p−qa(p+q)
5
4
3
2
1
Correct answer is B
√x2+9 = x + 1
x2 + 9 = (x + 1)2 + 1
0 = x2 + 2x + 1 - x2 - 9
= 2x - 8 = 0
2(x - 4) = 0
x = 4
If N225.00 yields N27.00 in x years simple interest at the rate of 4% per annum, find x
3
4
12
17
Correct answer is A
Principal = N255.00, Interest = 27.00
year = x Rate: 4%
∴ 1 = PRT100
27 = 225×4×T100
2700 = 900T
T = 3 years
Solve without using tables log5(62.5) - log5(12)
3
4
5
8
Correct answer is A
log5(62.5) - log5(12)
= log5(62.5)12 - log5(2 x 62.5)
= log5(125)
= log553 - 3log55
= 3
If 2log3 y + log3 x2 = 4, then y is
4 - log3
4log3x
4x
± 9x
Correct answer is D
2log3y + log3x2 = 4
log3y2 + log3x2 = 4
∴ log3 (x2y2) = log381(correct all to base 4)
x2y2 = 81
∴ xy = ±9
∴ y = ±9x