3
23
7
-4
Correct answer is D
1√3−2 - 1√3+2
L.C.M = (3- 2) (3 + 2)
∴ 1√3−2 - 1√3−2 = √3+2−√3−2√3−2+√3−2
√3+2−√3+23−2√3+2√3−4 = 43−2
= 4−1
= -4
Solve for y in the equation 10^1 x 5(2y - 2) x 4(y - 1) = 1
34
54
23
5
Correct answer is C
10y x 5(2y - 2) x 4(y - 1) = 1
but 10y - (5 x 2)y = 5y x 2y
= (Law of indices)
5y x 2y x 5(2y - 2) x 4(y - 1) = 1
but 4(y - 1) = 22(y - 1)
= 2y - 2 (Law of indices)
5y x 5(2y -2) x 2(- 2) = 1
5(3y -2) x 2y x 2(2y -2) = 1
= 5(3y -2) x 2(3y -2) = 1
But ao = 1
10(3y -2) = 10o
3y - 2 = 0
∴ y = 23
Find x
12
1
2
3
Correct answer is B
9(x - 12) 3x2 = 32(x - 12) = 3x2
∴ 2(x - 12) = x2
2x - 1 = x2
hence x2 - 2x + 1 = 0
(x - 1)(x - 1) = 0
x = 1
Evaluate 35240.05 correct to 3 significant figures
705
70,000
70,480
70,500
Correct answer is D
35240.05 = 70480
≈ 70500(3 s.g)