You purchase some school supplies. you buy 10 items that cost $4.00 in all. erasers cost 25 cents each, and pencils cost 50 cents each.

a. determine what x and y represent in the following system of equations representing your solution.
1/4x + 1/2y = 4
x+y=10

b. how many pencils did you purchase?

Solve the system of equations. y= 2x y= x^2 - 15

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered

Multiply and simplify. 2x^2 y^3 z^2 · 4xy^4 x^2 i will mark you brainliest if right. show how you got the answer, !