Answer:
Option D. (8, – 4)
Step-by-step explanation:
3x + 4y = 8 ..... (1)
x – y = 12.... (2)
To solve the above equation by elimination method, do the following:
Step 1:
Multiply equation 1 by the coefficient of x in equation 2 i.e 1.
Multiply equation 2 by the coefficient of x in equation 1 i.e 3. This is illustrated below:
1 × Equation 1
1 × (3x + 4y = 8)
3x + 4y = 8 ...... (3)
3 × Equation 2
3 × ( x – y = 12)
3x – 3y = 36......(4)
Step 2:
Subtract equation 3 from equation 4. This is illustrated below:
. 3x – 3y = 36
– (3x + 4y = 8)
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
– 7y = 28
Divide both side by the coefficient of y i.e –7
y = 28/–7
y = – 4
Step 3:
Substitute the value of y into any of the equation to obtain the value of x. In this case, we shall substitute the value of y into equation 2 as shown below:
x – y = 12
y = –4
x – (–4) = 12
x + 4 = 12
x = 12 – 4
x = 8
Therefore, the solution to the equation above is (8, – 4)
