Question

substitution method solve 4x+3y=17 9x+10y=28​

Answer 1

Answer:

x = 84 / 13  and y = - 196 / 65

Step-by-step explanation:

Given :

4 x + 3 y = 17

Multiply by 10

40 x + 30 y = 170

30 y = 170 - 40 x ..... ( i )

9 x + 10 y = 28

Multiply by 3

27 x + 30 y = 84

30 y = 84 - 27 x .....( ii )

From ( i ) and ( ii ) we have

170 - 40 x = 84 - 27 x

40 x - 27 x = 170 - 84

13 x = 84

x = 84 / 13    

Now putting x = 84 / 13  in equation

9 x + 10 y = 28

10 y = 28 - 9 x

10 y = 28 - 9 × 84 / 13

10 y = ( ​364 - 756 ) / 13

10 y = 392 / 13

y = 392 / 130

y = - 196 / 65

Thus we get x = 84 / 13  decimal value 6.61  and y = - 196 / 65 decimal value - 3.15