Relations and mapping

Consider a graph for the equation y= -3x+4. what is the y intercept? a) 4 b) -4 c) 3 d) -3

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

Hell . what are the solutions to `10x^2 - 38x - 8 = 0`? is this when i find the factors and use the numbers within the factors to determine the zeros? i hope that made sense lol