I need help finding x.​

4+6x-3x^3 in standard form with explanations because i don’t understand

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

Solve with work both bert and ernie received an increase in their weekly salaries. bert's salary increased from $520 to $520. ernie's salary went from $580 to $645. find the percent of increase for each salary. what was the larger of the two percents ?