Question

I don’t understand how do you solve the simultaneous.

Answer 1

y = 6 x = 1

To solve, get either the x or y with opposite numbers in the front in order to cancel one out. For example, -3 and 3
You already have that with the x (-x and x), so you cancel them out by adding the 2 equations.

When you add the x’s, they disappear. Then you add 3y to y (4y) and 7 to 17 (24). You’ll get the equation: 4y = 24.
Divide both sides by 4 to solve for y, which is 6!

Next, choose any of the equations in the question and instead of y, use 6. Let’s use: x + y = 7
When you replace y with 6, it becomes x + 6 = 7.

And x = 1.

Answer 2

Given:-

• 
  `\sf \: x + y = 7 - - - eqⁿ ( 1 )`

`\:`

• 
  `\sf{-x +3 y =1 7 - - - eqⁿ ( 2 )}`

`\:`

now , Add the eqⁿ( 1 ) to ( 2 ) ∼

`\rm \: \: \: \: \cancel {x} + y \: \: = \: 7 \\ \rm \: \cancel {- x} + 3y = 17 \\ ————————— \\ \rm \: \: \: \: \: \: \: \: \: \: \: \: \: 4y = 24 \\ \rm \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: y = \cancel(24)/(4) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \boxed{ \rm \color{hotpink}{ y = 6 \: }}`

now , pur the value of y = 6 in eqⁿ ( 2 )

`\sf- x + 3( 6 ) = 17 \\ \: \: \: \sf- x + 18 = 17 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf-x = 17- 18 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf \cancel -x = \cancel - 1 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \boxed{ \purple{ \sf \: x = 1 \: }}`

`\:`

hope it helps! :)