How do I determine if each equation is non linear? Which ones are linear, and which ones aren't?

y = x/2 - 19, 3y = x^2, 13y = 1/3x + 5, y = x + 25/5, y^3 = x

Guys i really need or i have to stay late up night

Adriana sold 50 shares of a company’s stock through a broker. the price per share on that day was $22.98. the broker charged her a 0.75% commission. what was adriana’s real return after deducting the broker’s commission? a. $8.62 b. $229.80 c. $1,140.38 d. $1,149.00

What can each term of the equation be multiplied by to eliminate the fractions before solving? x – + 2x = + x 2 6 10 12