Question

solve the following equation by substituting method 2x+3y=7:3x-y=5 ​

Answer 1

Answer:

2x−3y=7

5x+y=9

y=9−5x

Now, substitute equation (2) in equation (1)

Then ,2x−3(9−5x)=7

2x−27+15x=7

17x=27+7

17x=34

x=34/17=2

y=9−5×2=9−10=−1

Therefore x is 2 and y is −1

plzz mark as brilliant

Answer 2

Sᴏʟᴜᴛɪᴏɴ :

$\sf \: 2x + 3y = 7.......(1) \\ \sf \: 3x - y = 5.........(2)$

From Equation (1)

$››\sf \: 2x + 3y = 7 \\››\sf \: 2x = 7 - 3y \\ \\ ››\sf \: x = \frac{7 - 3y}{2} \: \: \: \: \: \: \: \: \quad ..........(3)$

Substituting value of x in (2)

$››\sf \: 3x - y = 5 \\ \\ ››\sf \: 3( \frac{7 - 3y}{2} ) - y = 5 \\ \\››\sf \: \frac{21 - 9y}{2} - y = 5 \\ \\ ››\sf \: \frac{21 - 9y - 2y}{2} = 5 \\ \\ ››\sf \: 21 - 11y = 10 \: \: \: \\ \\ ››\sf \: - 11y = 10 - 21 \\ \\ ››\sf \: - 11y = - 11 \\ \\ ››\sf \: y = \cancel\frac{ - 11}{ - 11} \\ \\ ››\sf \pink{y = 1}$

Substituting value of y in (3)

$››\sf \: x = \frac{7 - 3y}{2} \\ \\ ››\sf \: x = \frac{7 - 3 \times 1}{2} \\ \\ ››\sf \: x = \frac{7 - 3}{2} \\ \\ ››\sf \: x = \cancel \frac{4}{2} \\ \\ ››\sf \: \pink{x = 2}$

$\large\dag \large { \red{\underline{\bf{Hence }}}}$

• value of x is 2 and value of y is 1