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`