Answer:
6x - 5y = 15 and x + 2y = 0
Explanation:
Here we are given the following equations:
i) x-2y= 4
ii) 4x+5y= 8
iii) 6x-5y=15
iv) x+2y=0
Required:
Which system of equations has a solution of approximately (1.8, –0.9).
To find the approximate equations, substitute x and y for 1.8 and -0.9 into all the equations respectively and check the resulting values
i) Substitute (1.8, -0.9) in x-2y= 4:
1.8 - 2(-0.9) = 4.
1.8 + 1.8 = 4.
3.6 ≠ 4.
ii) Substitute (1.8, -0.9) in 4x+5y= 8
4(1.8) + 5(-0.9) = 8
7.2 - 4.5 = 8.
2.7 ≠ 8.
iii) Substitute (1.8, -0.9) in 6x-5y=15
6(1.8) - 5(-0.9) = 15.
10.8 + 4.5 = 15
15.3 ≠ 15.
This equation has a solution that is close, therefore it is correct.
iv) Substitute (1.8, -0.9) in x+2y=0
1.8 + 2(-0.9) = 0.
1.8 - 1.8 = 0.
0 = 0.
x + 2 y = 0 has the exact value, therefore it is also correct.
The system of equations that has a solution of approximately (1.8, –0.9) are:
x+2y=0 and 6x-5y=15