There are 4 positive integers a, b,c, d, such that 4cos(x)cos(2x)cos(4x) = cos(ax)+cos(bx)+cos(cx)+cos(dx) for all values of x. find a+b+c+d.?

Which of the following lines does not intersect the line y=-2x+3 ? a) y=2x b) y=2x-3 c) y=2x+3 d) y=-2x-3

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.

The price of a dozen eggs was $1.63. suppose the price increases m dollars per dozen and then the price decreases $0.12 per dozen. which expression represents the current price of eggs after the two price changes?