Question

Solve by Crammer's rule (dererminents)
5x+2y=3
3x+2y=5​

Answer 1

Answer:

5x+2y=3________________(1)

3x+2y=5________________(2)

by equation (1)

$x = \frac{3 -2y}{5} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (3)$

by (2)and(3),

$3 \times \frac{(3 - 2y)}{5} + 2y = 5 \\ \longrightarrow \: \frac{9 - 6y}{5} + 2y = 5 \\ \longrightarrow \frac{9 - 6y + 10y}{5} = 5 \\ \longrightarrow \frac{9 + 4y}{5} = 5 \\ \longrightarrow 9 + 4y = 5 \times 5 = 25 \\ \longrightarrow \: y = \frac{25 - 9}{4} \\ \longrightarrow \: y = \frac{16}{4} = 4 \: \: \: \: \: \: (4) \\ by \: (1)and(4) \\ 5x + 2y = 3 \\ 5x = 3 - 2 \times 4 \\ 5x = 3 - 8 = - 5 \\ x = \frac{ - 5}{5} = - 1$