Solve the simultaneous equations 3x+y=8 X-3Y=11

(7/2, - 5/2)

Step-by-step explanation:

We can solve this multiple ways: Algebraically (Substitution or Elimination) or Graphically

Step 1: Write 1st equation in terms of y

y = 8 - 3x

Step 2: Substitute y of 2nd equation

x - 3 (8 - 3x) = 11

Step 3: Solve for x

x - 24 + 9x = 11

10x - 24 = 11

10x = 35

x = 7/2

Step 4: Plug x to find y

3 (7/2) + y = 8

21/2 + y = 8

y = - 5/2

Step-by-step explanation:

let's organize our information:

3x+y=8 x-3y=11

The trick here is to multiply x-3y=11 by - 3 then add it to 3x+y=8 to get rid of x and get a normal equation

we get : - 3x+9y = (-33)

then after the addition : 3x+y-3x+9y=8-33⇔ 10y = (-25)

so y = (-25) / 10 = - 5/2

let's replace y by - 5/2 in 3x+y=8 3x-5/2 = 8⇔ x = 21/6

so y = (-5/2) and x = 21/6