Question

Solve the following system of linear equations by substitution method :
7 x - 5y = 2
x + 2 y = 3​

Answer 1

Solution :-

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

Substitute value of x from ( 2 ) into ( 1 )

$\sf \implies 7x - 5y = 2 \\ \\ \sf \implies7(3 - 2y) - 5y = 2 \\ \\ \sf \implies21 - 14y - 5y = 2 \\ \\ \sf \implies - 19y = 2 - 21 \\ \\ \sf \implies - 19y = - 19 \\ \\ \sf \implies y = \frac{ - 19}{ - 19} \\ \\ \implies \underline{ \boxed{ \sf y = 1}}$

Substitute value of y in ( 2 ) to find value of x

$\sf \implies x = 3 - 2y \\ \\ \sf \implies x = 3 - 2 \times 1 \\ \\\sf \implies x = 3 - 2 \\ \\ \implies \underline{\boxed{ \sf x = 1}}$

Answer 2

Answer:

x=2

y=

Step-by-step explanation:

7x-5y=2-----------] (1)

x+2y=3-----------](2)

7x=2+5y

x=2+5y/7---––--](3)

subsitute 3 in 2

2+5y/7+2y=3

2+5y+2y=3×7=21

7y=21-2

7y=19

y=19/7

y=2.7142