X + 2y = 7
x - y = 1

Solve for x and y?

y=2

x=3

Step-by-step explanation:

make x - y = 1 into x= y + 1

put that wherever x is in the other equation

so y + 1 + 2y =7. then combine like terms into 3y =6. then divide 6 by 3 so you get y = 2

then substitute 2 into the y in the equation x - y = 1 and you get x = 3

METHOD OF ELIMINATION:

Given pair of linear equations are:

x+2y= 7 – – – Eqn(i)

On comparing with a1x+b1y+c1 = 0

x-y = 1 – – – Eqn(ii)

On comparing with a2x+b2y+c2 = 0

a1/a2 = 1/1 = 1

b1/b2 = 2/-1 = -2

c1/c2 = -7/-1 = 7

We have,

a1/a2 ≠ b1/b2 ≠ c1/c2

So, Given pair of linear equations in two variables have a unique solution.

Now,

On Subtracting eqn(ii) from eqn(i) then

x+2y = 7

x-y = 1

(-)

0 +3y = 6

⇛ 3y = 6

⇛ y = 6/3

⇛ y = 2

On Substituting the value of y in (1) then

⇛ x-2 = 1

⇛ x = 1+2

⇛x = 3

Answer: Therefore , the value of x and y with be (3,2) respectively.

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