If two roots of the quadratic equation (b-c)x²_2(ac+bd)x+(c²+d²)=0 are equal, then let us prove that, a/b=c/d.

help me !
plzz

​

Aresearch company wants to test the claim that a new multivitamin to improve short term memory. state the objective of the experiment, suggest a population, determine the experimental and control groups, and describe a sample procedure.

If x = 12 and y = 3, what is the value of x - y 2? 81 6 3 18

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