Question

Can the following equations hold simultaneously?
3x – 7y = 7
11x + 5y = 87
5x + 4y = 43.
If so, find x and y.sove by elimination method ​

Answer 1

Step-by-step explanation:

here three equations are given you can take any 2 equations to solve and verify by putting the values in 3 equation.

1. multiply 3x-7y=7 by 11

2. multiply 11x+5y by 3

3. now the equation becomes 33x-77y=77 (a) and 33x+15y=261(b)

4. now do b-a you will get 33x+15y-33x+77y=261-77

5.92y=184=> y=2

6. put value of y in any equation and get value of x,x=7

i hope this prooves useful

3x=7+7y

x=7/3(1+y)

5(7/3(1+y))+4y=43

35/3(1+y)+4y=43

35/3 y+4y=43-35/3

47/3 y=94/3

y=94/47=2

3x-7(2)=7

3x=21

x=21/3=7

hope u understand

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Answer 2

Answer:

3x- 7y= 7 (1) ×20

11x+ 5y=87 (2) × 28

5x + 4y = 43 (3) ×35

20mulitiple equation (1)

28mulitiple equation (2)

35multiple equation (3)

60x- 140y =140

308x- 140y = 2436

175x+ 140y = 1575

cut 140

60x +308+175 =543x

140+2436+1575 =4081

4081 / 543 = 7

x=7

then , 21- 7y = 7

- 7y =7- 21

- 7y = 14

14 by 7 = 2

therefore y= 2