JAMB Mathematics Past Questions & Answers - Page 289

1,441.

The 4th term of an A.P. is 13 while the 10th term is 31. Find the 21st term.

A.

175

B.

85

C.

64

D.

45

Correct answer is C

a + 3d = 13

a + 9d = 31

6d = 18

= d = 3

a = 13 - 9

= 4

a + 20d = 4 + (20 x 3)

= 64

1,442.

Solve the inequality (x - 3)(x - 4) \(\leq\) 0

A.

3 \(\leq\) x \(\leq\) 4

B.

3 < x < 4

C.

3 \(\leq\) x < 4

D.

3 < x \(\leq\) 4

Correct answer is A

(x - 3)(x - 4) \(\leq\) 0

Case 1 (+, -) = x - 3 \(\geq\) 0, X - 4 \(\geq\) 0

= X \(\leq\) 3, x \(\geq\) 4

= 3 < x \(\geq\) 4 (solution)

Case 2 = (-, +) = x - 3 \(\leq\) 0, x - 4 \(\geq\) 0

= x \(\leq\) 3, x \(\geq\) 4

therefore = 3 \(\leq\) x \(\leq\) 4

1,443.

Factorize completely the expression \(abx^2 + 6y - 3ax - 2byx\)

A.

(ax - 2y)(bx - 3)

B.

(bx + 3)(2y - ax)

C.

(bx + 3)(ax - 2y)

D.

(ax - 2y)(ax - b)

Correct answer is A

\(abx^{2} + 6y - 3ax - 2byx\)

Collecting like terms, we have

\(abx^{2} - 3ax + 6y - 2byx\)

= \(ax(bx - 3) + 2y(3 - bx)\)

= \(ax(bx - 3) - 2y(bx - 3)\)

= \((ax - 2y)(bx - 3)\)

1,444.

The graph of f(x) = x2 - 5x + 6 crosses the x-axis at the points

A.

(-6, 0), (-1, 0)

B.

(-3, 0), (-2,0)

C.

(-6, 0),(1, 0)

D.

(2, 0), (3, 0)

Correct answer is D

When X = 3, Y = 0(3, 0),

When x = 2, y = 0(2, 0)

1,445.

Finds a positive value of p if the expression 2x2 - px + p leaves a remainder 6 when divided by x - p and q

A.

1

B.

2

C.

3

D.

4

Correct answer is B

x - p,x = p

2p2 - p2 + p = 6

= p2 + p - 6

= 0

p = 3, 2