Question

3x - y = 7; * * 4y = 11​

Answer 1

Answer:

3x - 4 = 7

3x = 7+4

3x = 11

x = 11/3

Answer 2

Answer:

$\huge\boxed{x=\dfrac{13}{4};\ y=\dfrac{11}{4}}$

Step-by-step explanation:

$\left\{\begin{array}{cccc}3x-y=7&&&(1)\\4y=11&\to&y=\dfrac{11}{4}&(2)\end{array}\right$

substitute (2) to (1)

$3x-\dfrac{11}{4}=7\\\\4\cdot3x-4\cdot\dfrac{11}{4}=4\cdot7\\\\12x-11=28\\+11\qquad+11\\\\12x=39\\\\\dfrac{12x}{12}=\dfrac{39}{12}\\\\x=\dfrac{39:3}{12:3}\\\\x=\dfrac{13}{4}$