Which of the following lines goes downwards from left to right? a. y=2x+5 b. y=2x-6 c. y=2x d. y=-2x+20

"Goes downwards from left to right" is basically saying that the slope of this line is negative. We go downhill from left to right. 

y = 2x+5 has a positive slope because m = 2 is the slope (b = 5 is the y intercept)
So choice A is out

Similarly choice B is eliminated as well because the slope is also m = 2

Choice C is false as well. The slope here is m = 2 (think of y = 2x as y = 2x+0)

The only choice with a negative slope is choice D. The slope is m = -2 

This is why the answer is choice D

Side Note: I'm using slope intercept form y = mx+b where m is the slope and b is the y intercept

Hello!

the answer is:

the answer is:

why?

to solve the problem, we need to remember the quotient of power property, it's defined by the following relation:

if we have a quotienf of powers that have the same base, we need to keep the same base and subtract the exponent of the denominator power to the exponent of the numerator power.

so, we are given the expression:

then, calculating we have:

hence, the answer is:

have a nice day!