What does 5.9E4 mean?

What is the solution to the equation e3x=12? round your answer to the nearest hundredth

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle. what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle. what is the measure of angle a? enter your answer in the box. m∠a= 3.)quadrilateral abcd is inscribed in this circle. what is the measure of angle b? enter your answer in the box. m∠b= °4.)quadrilateral abcd is inscribed in this circle. what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle. what is the measure of angle c? enter your answer in the box.°

Solve this 364x-64x=300x and 12(x2–x–1)+13(x2–x–1)=25(x2–x–1)