We are given that
An ion has a charge of +7
and a neutral has charge always 0
so, change is charge = ion charge - neutral change
so, we can plug values
change is charge = +7 -0
change is charge = 7
so, option-C..................Answer
The XY is dilated by a scale factor of 1.3 with the origin as the center of dilation to create the X'Y'. So the length of X'Y' is 1.3 times of origin but the slope is the same. The slope is m
45*31=1,395
that would be 1,395 gallons if water used in december.
We use scientific notation when either the questions asks for it or when the number is really long or really short...