I NEED HELP PLSS WILL GIVE BRAINLIEST STEP BY STEP

vxy-4+4by

x = 1
b= -2
y = -1
v = 3

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

The manufacturer of a new product developed the following expression to predict the monthly profit, in thousands of dollars, from sales of the productwhen it is sold at a unit price of x dollars.-0.5x^2 + 22x - 224what is represented by the zero(s) of the expression? a.the profit when the unit price is equal to 0b.the unit price(s) when the profit is equal to 0c.the profit when the unit price is greatestd.the unit price(s) when profit is greatest