Question

If y varies directly as x, find y: {(8, -12). (20, y)}

Answer 1

$\\ \sf\longmapsto x_1y_2=x_2y_1$

$\\ \sf\longmapsto 8y=-12(20)$

$\\ \sf\longmapsto 8y=-240$

$\\ \sf\longmapsto y=-240/8$

$\\ \sf\longmapsto y=-60$