Question

3x - 5y-4= 0 and 9x = 2y + 7 by elemination method​

Answer 1

Step-by-step explanation:

$3x - 5y = 4 \: \: \: \: \: \: (i) \\ 9x - 2y = 7 \: \: \: \: \: \: (ii) \\ multiplying \: eqn \: i \: with \: 3 \\ 3(3x - 5y = 4) \\ 9x - 15y = 12 \: \: \: \: \: \: (iii) \\ subtract \: eqn \: iii \: from \: ii \\ 9x - 2y = 7 \\ 9x - 15y = 12 \\ \frac{ - \: \: \: \: \: + \: \: \: \: \: = - }{13y = - 5} \\ y = \frac{ - 5}{13} \\ use \: value \: of \: y \: in \: eqn \: i \\ 3x - 5( \frac{ - 5}{13} ) = 4 \\ 3x + \frac{25}{13} = 4 \\ 3x = 4 - \frac{25}{13} \\ 3x = \frac{52 - 25}{13} \\ 3x = \frac{27}{13} \\ x = \frac{27}{13} \div 3 \\ x = \frac{27}{13} \times \frac{1}{3} \\ x = \frac{27}{39} \\so \: x = \frac{27}{13} \: \: \: y = \frac{ - 5}{13}$

a