What is the dependent variable?
the more time david spent playing video games, the lower his grades became.

a) number of video games owned
b) points earned playing video games
c) david's time playing video games
d) david's grades

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have