Perform the operation to simplify (-2x^4 + x^2 - x - 9) + (x^4 -x^3 -5x +3)

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

Use multiples to write two fractions equivalent to 7/9. 14/18, 8/10 6/8, 21/27 10/12, 28/36 14/18, 21/27

How can (square root of 25) ^2 be rewritten?