Question

tell me answer fast please

Answer 1

$let \: \frac{1}{3x + y} = u \\ \frac{1}{3x - y} = v \\ u + v = \frac{3}{4} \\ 4u + 4v = 3 \: \: \: \: \: eq1 \\ \frac{u}{2} - \frac{v}{2} = \frac{ - 1}{8} \\ 4u - 4v = - 1 \: \: \: \: \: eq2 \\ add \: both \: eq \\ 8u = 2 \\ u = \frac{1}{4} \\ 4 \times \frac{1}{4} + 4v = 3 \\ 4v = 2 \\ v = \frac{1}{2} \\ \\ put \: these \: value \: in \: initial \: assumption \\ \frac{1}{3x + y} = \frac{1}{4} \\ 3x + y = 4 \\ \frac{1}{3x - y} = \frac{1}{2} \\ 3x - y = 2 \\ on \: adding \: both \: eq \\ 6x = 6 \\ x = 1 \: \: \: ans \\ 3x - y = 2 \\ 3 - y = 2 \\ - y = 2 - 3 \\ y = 1 \: \: \: ans$