Question

3x+4y+5=0;y=x+4 equation​

Answer 1

$\huge \mathbb\fcolorbox{black}{lightcyan}{Answer}$

$3x + 4y + 5 = 0 \\ 3x + 4(x + 4) + 5 = 0 \\ 3x + 4x + 16 + 5 = 0 \\ 7x + 21 \\ 7x = - 21 \\ x = \frac{ - 21}{7} \\ x = - 3$