Please help me :( this is so so hard.

The sum of the reciprocal of a positive number and the reciprocal of 2 more than the number is 3/4 equation: the number is

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

Ntriangle abc, m∠a = 35° and m∠b = 40°, and a=9. which equation should you solve to find b?