An engineering student answered 81 questions correctly on a 90-question test. What percent of the questions did she answer incorrectly?

He amount of carbon-14 present in animal bones t years after the animal's death is given by p(t)equals=upper p 0 e superscript negative 0.00012097 tp0e−0.00012097t. how old is an ivory tusk that has lost 26% of its carbon-14?

Brent wants to know what is 5 x 1/2

What is the value of x in the equation 2(x-4) = 4(2x + 1)?