JAMB Mathematics Past Questions & Answers - Page 360

1,796.

If 2x\(^2\) - kx - 12 is divisible by x-4, Find the value of k.

A.

4

B.

5

C.

6

D.

7

Correct answer is B

2x2 - kx - 12 is divisible by x-4
implies x is a factor ∴ x = 4
f(4) implies 2(4)2 - k(4) - 12 = 0
32 - 4k - 12 = 0
-4k + 20 = 0
-4k = -20
k = 5

1,797.

Make Q the subject of formula when \(L=\frac{4}{3}M\sqrt{PQ}\)

A.

\(\frac{9L^2}{16M^2P}\)

B.

\(\frac{3L}{4M\sqrt{P}}\)

C.

\(\frac{\sqrt{3L}}{4MP}\)

D.

\(\frac{3L^2}{16M^2}P\)

Correct answer is A

\(L=\frac{4}{3}M\sqrt{PQ}\\
=\frac{3}{4M} \times L = \sqrt{PQ}\\
=\left(\frac{3L}{4M}\right)^2=(\sqrt{PQ})^2\\
=\frac{9L^2}{16M^2}=PQ\\
=Q=\frac{9L^2}{16M^2 P}\)

1,799.

If X = {n\(^2\) + 1:n = 0,2,3} and Y = {n+1:n=2,3,5}, find X∩Y.

A.

{1,3}

B.

{5,10}

C.

D.

{4,6}

Correct answer is C

X = {1,5,10}
Y = {3,4,6}
X∩Y = ∅

1,800.

If \(\frac{1+\sqrt{2}}{1-\sqrt{2}}\) is expressed in the form of x+y√2 find the values of x and y

A.

(-3, -2)

B.

(-2, 3)

C.

(3,2)

D.

(2,-3)

Correct answer is A

\(\frac{1+\sqrt{2}}{1-\sqrt{2}} \times \frac{1+\sqrt{2}}{1+\sqrt{2}}\\
=\frac{1+(1+\sqrt{2})+\sqrt{2}(1+\sqrt{2})}{1^2 - (\sqrt{2})^2}\\
=\frac{(1+\sqrt{2}+\sqrt{2}+2)}{1-2}\\
=\frac{3+2\sqrt{2}}{-1}\\
=-3-2\sqrt{2}\\
∴X and Y = -3 and -2\)