Question

Solve the following pair of linear equations using substitution method :-

2x+3y + 5 = 0 ; 5x-3y+9=0​

Answer 1

Step-by-step explanation:

$2x + 3y + 5 = 0 \\ or \: \: 2x + 3y = - 5 \\ 5x - 3y + 9 = 0 \\ or \: \: 5x - 3y = - 9 \\ \\ 2x + 3y = - 5 \times 5 \\ 5x - 3y = - 9 \times 2 \\ 10x + 15y = - 25 \\ 10x \: \: - \: 6y \: = - 18 \\ - \: \: \: \: \: \: \: + \: \: \: \: = \: \: + \\ 21y = - 7 \\ or \: \: y = - \frac{7}{21} = - \frac{1}{3} \\ \\ 2x + 3 \times ( - \frac{1}{3}) = - 5 \\ or \: \: 2x - 1 = - 5 \\ or \: \: 2x = - 5 - 1 \\ or \: \: x = \frac{ - 6}{2} = - 3 \\ hence \: \: \: \: x = - 3 \\ y = - \frac{1}{3}$