Question

solve the following system of equation by substituting method.
4. 7x – 2y = 1
3x + 4y = 15​

Answer 1

Answer:

X= 1 & Y =3

According to first equation -

7x = 1 + 2y

x = 1 + 2y/7

substitue in equation no. 2

3(1+2y)/7 +4y = 15

(3+6y)/7 + 4y = 15

3+6y + 28y = 105 ( multiply by 7)

34y = 105 - 3

y = 102/34 = 3

NOW

put the value of y in 1st equation.

7x - 2(3) = 1

7x = 7

x = 1

Answer 2

Answer:

7x - 2y = 1

=>7x = 1 + 2y

=>x = (1 + 2y)/7 -----(i)

Using (i) in eqn2, we have,

=>3*(1 + 2y/7) + 4y = 15

=>3 + 6y/7 + 4y = 15

lcm = 7

=>(3 + 6y/7) + (28y/7) = 15

=>34y + 3 = 105

=>34y = 102

=>y = 3

Using y = 3 in eqn1,

=>7x - 6 = 1

=>7x = 7

=>x = 1

So, x = 1 and y = 3

Hope it helps