What goes in the highlighted box?

Which of the following equations are equivalent to -2m - 5m - 8 = 3 + (-7) + m? -15m = -4m -7m - 8 = m - 4 -3m - 8 = 4 - m m - 4 = -7m - 8 -8 - 7m = -4 + m -8 - 3m = 4 - m

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

A+b= 17, ab=70, find the value of |a-b|