Question

If y=-4 when x=10, determine y when x=5.

Answer 1

$y=-4 \\ x=10 \\ \\y =? \\ x=5 \\ ---------------- \\ {\left \{ {{y=-4} \atop {x=10}} \right. }/ :2 \\ \\ {\left \{ {{\boxed{y=-2} \atop {x=5}} \right. } \\ \\ \text{Answer: y=-2}$