Answer:

Remove backets

Group and Evaluate like terms





So we want to know what do we need to measure to determine the wavelength of the wave on the image. A wavelength is the distance between peaks of the wave. More generally, the distance on which the wave shape repeats. So on the image we need to measure X to determine the wavelength. So the correct answer is X.
The greatest common factor is 7 .
This is an arithmetic sequence (graph is a line), so function:
a(n) = First term + (n-1) * Common Difference
Here First term = 42 and Common difference = 34 - 36 = -2 so

Answer B.
So if two is fifty, divide it by two to get twenty five, multiply that by three to get seventy five. 3x=75