How many 4 digit numbers can be created from the digits 7.3.1,8,3 and 4

Which of the following is the equation of a line that passes through the point (1,4) and is parallel to the x-axis a. y=1 b. y=4 c. x=1 d. x=4

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles.

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