Express the imaginary number -5i as a complex number

Nine more than four times a number is the same as one less than twice the number. find the number?

Abouncy ball is released from a certain height. on the first bounce, it travels 32cm. with each subsequent bounce, it travels 9/10 the distance of the previous bounce. what is the total distance that the ball has traveled when it completes its 25th bounce?

Solve each quadratic equation by factoring and using the zero product property. x^2 + 18x = 9x