Evaluate the following expressions if a = 2, b = -3, c = -1, and d = 4. then solve for
2a + C

Adolphin is swimming with her friend. the dolphin jumps to a height of 4.54.54, point, 5 meters above the surface of the water as her friend swims 9.89.89, point, 8 meters directly below her. what is the position of the dolphin's friend relative to the surface of the water? meters

Moesha is (3g+1) years old and shanti is twice moesha age. find the sum of the ages of moesha and shanti in 2 years time. how old will shanti be when moeshas age in twice her present age? find how old moesha and shanti were 4 years ago if g= 5

Azookeeper predicted the weight of a new baby elephant to be 233 pounds when it was born. the elephant actually weighed 265 pounds at birth. what was the percent error of the zookeeper's prediction? asap