–7.5 + ( –7.6)

sorry but i don't understand

Acar traveling at 65 mph leaves 25 foot skid mark what is the ratio of the speed to length of skid mark (feet) in the simplest form

The acceleration of an object due to gravity is 32 feet per second squared.what is acceleration due to gravity in inches per second squared?

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.