Simplify. 10y(3x – 7z)

30xy – 70yz
103xy – 107yz
30xy – 7z
3x – 70yz

Distribute

10y × 3x + 10y × -7z

Simplify 10y × 3x to 30yx

30yx + 10y × -7z

Simplify 10y × -7z to -70yz

30xy - 70yz

A. 30xy - 70yz

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."