Niobium-91 has a half-life of 680 years. After 2,040 years, how much niobium-91 will remain from a 300. 0-g sample? 3 g 18. 75 g 37. 5 g 100. 0 g.

Amount of Niobium-91 initially

= 300/91 =3.2967mol

2040 years = 3 ×680 = 3 half-lives

therefore, amount left = 0.4121mol

mass of Niobium-91 remaining = 0.4121 ×91 =37.5g

Please give brainliest

answer: answer

step-by-step explanation:

fa tha first one you gonna add y to both sides

it look like this

x-y+y=6+y

x=y+6

therefore your answer is

x =y+6

fa tha second one

you gonna flip tha equation

it gonna look like x-4y=y

then add 4 to both sides

it gonna look like tha

x-4 +4 =y +4

so therefore tha answer is x=y+4

step-by-step explanation: