CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Question 1 (iii)
Solve the following pair of linear equations by the elimination method and the substitution method:
3x - 5y - 4 = 0 and 9x = 2y + 7


Open in App
Solution

3x - 5y - 4 = 0 and 9x = 2y + 7

By elimination method:

3x5y4=0
3x5y=4...(i)
9x=2y+7
9x2y=7...(ii)
Multiplying equation (i) by 3, we get
9x15y=12...(iii)

And we have
9x2y=7...(ii)

Subtracting equation (ii) from equation (iii), we get
-13y = 5
y=513

Putting value in equation (i), we get
3x - 5y = 4 ... (i)
3x5(513)=4

Multiplying by 13, we get
39x + 25 = 52
39x = 27

x=2739=913

Therefore, x=913 and y=513

By substitution method:

3x – 5y = 4 ... (i)
Adding 5y on both sides, we get
3x = 4 + 5y
Dividing by 3, we get,
x=4+5y3 ... (iv)
Putting this value in equation (ii) we get,
9x - 2y = 7 ... (ii)
9(4+5y)32y=7

3(4+5y)2y=7
12+15y2y=7
13y=5

y=513

Substituting the value in equation (iv), we obtain:

x=4+5×5133

x=913

x=913,y=513

Hence, we get x=913 and y=513


flag
Suggest Corrections
thumbs-up
6
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon