PLS HELP ME WITH GEOMETRY PLSAND THANK YOU

Which value is not a solution of 8x^3 – 1 = 0

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9