Question

3x + y =11
5x - y = 21

Answer 1

3x + y = 11 (3rd equation)
5x - y = 21 (4th equation)

Add (3rd equation and 4th equation)

3x + 5x = 32 (+y and -y got canceled)
=> 8x = 32
=>x = 4


(Substitute x with equation 3)

3x + y = 11
=> 12 + y = 11
=> y = -1

Answer 2

`\bold{Heya...}`

3x + y = 11.

E x p l a n a t i o n : -

Let's solve for x ~

3x + y = 11

Step 1: Add -y to both sides.

`\mathtt{3x \: + \: y \: + \: -y \: = \: 11 \: + \: -y}`

`\mathtt{3x \: = \: -y \: + \: 11}`

Step 2: Divide both sides by 3.

`\mathtt{(3x)/(3) \: = \: (-y \: + \: 11)/(3)}`

↓
`\underline{A \: n \: s \: w \: e \: r :}` ↓

`\bold{x \: = \: (-1)/(3)y \: + \: (11)/(3)}`

Let's solve for x ~

5x - y = 21.

Step 1: Add y to both sides.

`\mathtt{5x \: - \: y \: + \: y \: = \: 21 \: + \: y}`

`\mathtt{5x \: = \: y \: + \: 21}`

Step 2: Divide both sides of 5.

`\mathtt{(5x)/(5) \: = \: (y \: + \: 21)/(5)}`

↓
`\underline{A \: n \: s \: w \: e \: r :}` ↓

`\bold{x \: = \: (1)/(5)y \: + \: (21)/(5)}`

Hope It Helps U...

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