How to convert a number to scientific notation on a ti-84?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

Question 6(multiple choice worth 5 points) (05.02 lc) what is the value of x? a right angle is shown divided into two parts. the measure of one part of the right angle is 10 degrees. the measure of the other part is 2x 20 40 45 85

Which of the following exponentially equations is equivalent to the logarithmic equation below?