Hello my name is i'm 12 years old i need help

Hiroki wrote a number that is the opposite of -3. what number did hiroki write? a. ⅓ b. 3 c. 0 d. -3

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

Lines a and b are parallel. what is the value of x? -5 -10 -35 -55