Answer:
C. 
Step-by-step explanation:
Alan and his classmates found that the line of best fit through the data had the equation 
The slope of this line is 
If a line would intersect this line of best fit at right angles, then the two lines are perpendicular to each other.
The slopes of perpendicular lines are negative reciprocals of each other,
Hence that line must have slope 
Therefore we look for a line whose slope is
from the given options.
That line is the third option 
Answer:
C
Step-by-step explanation:
look up rules of multiplying radicals.
You can multiply the radicands (the number inside the square root) then take the square root of the new number.
3*21 = 63
Factor 63 into 3*3*7
Pull out 3^2 from inside the square root
leaves you with 3sqrt7 or answer C
I don't know what the "lowest y-intercept means" so if you can reiterate and clarify I'd appreciate it, but if you understand what you're looking for then I assume that a graph would be helpful. An online useful graphing site I like is desmos. Hope I helped.
Answer:
the answer is c
Step-by-step explanation:
y = 5x
as it says x + y = 10
so one number which is represented as x is times 5 as the other which brimg to our answer y =5x