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WAEC Mathematics 2021 Paper

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Question : 13

Total: 49

If 4x+2y=16 and 6x-2y=4 , find the value of (y-x).

8
2
4
6

Solution:

Concept:

Solving a pair of linear equations to find the values of

x

and

y

, then evaluating

(y-x)

.

Explanation:

Given equations are:

4x + 2y = 16

... (i)

6x - 2y = 4

... (ii)

Add equations (i) and (ii):

(4x + 6x) + (2y - 2y) = 16 + 4

10x = 20

x = 2

Substitute

x = 2

into equation (i):

4(2) + 2y = 16

8 + 2y = 16

2y = 8

y = 4

Therefore,

y - x = 4 - 2 = 2

Answer:

(y-x) = 2

Correct option: B. 2

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