Solve. URGENT PLS

b=3/4a

a+b=21

what is a what is b?!

Find all the values of x that make 0.1x + 0.25(102 - x) < 17.10 true.

Colby and jaquan are growing bacteria in an experiment in a laboratory. colby starts with 50 bacteria in his culture and the number of bacteria doubles every 2 hours. jaquan starts with 80 of a different type of bacteria that doubles every 3 hours. let x equal number of days. colbys experiment follows the model: a.) y=50*2^x b.) y=50*2^8x c.) y=50*2^12x jaquans experiment follows the model: a.)80*2^x b.)80*2^8x c.)80*2^12x

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)