If x = 3(y − 2z), find the value of x when y = 5 and z = 2. (i need this fast pls)

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Acircle has a circumference of 28.36 units what is the diameter of the circle

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.