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.

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

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

$\bold{x \: = \: \frac{-1}{3}y \: + \: \frac{11}{3}}$

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.

$\mathtt{\frac{5x}{5} \: = \: \frac{y \: + \: 21}{5}}$

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

$\bold{x \: = \: \frac{1}{5}y \: + \: \frac{21}{5}}$

Hope It Helps U...

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