Test Index

WAEC Mathematics 2023 Paper

© africaexams.com

Question : 47

Total: 50

If 2x - 3y = -11 and 3x + 2y = 3, evaluate

(y - x)^2

16
25
9
4

Solution:

Concept:

Solve the pair of linear equations to find

x

and

y

, then substitute into the expression

(y - x)^2

.

Explanation:

Given equations:

2x - 3y = -11

... (1)

3x + 2y = 3

... (2)

Multiply equation (1) by 3:

6x - 9y = -33

... (3)

Multiply equation (2) by 2:

6x + 4y = 6

... (4)

Subtract equation (3) from equation (4):

(6x + 4y) - (6x - 9y) = 6 - (-33)

13y = 39

y = \frac{39}{13} = 3

Substitute

y = 3

in equation (2):

3x + 2(3) = 3

3x + 6 = 3

3x = -3

x = \frac{-3}{3} = -1

Now evaluate the expression:

(y - x)^2 = (3 - (-1))^2

= (3 + 1)^2

= 4^2 = 16

Answer:

16

(Option A)

© africaexams.com

Go to Question:

Prev Question

Next Question