Answer:
Step-by-step explanation:
2x+5x+3=0
7x+3=0
-3 -3
=0 =-3
7x=-3
-3/7=-0.42857142857
x=-0.42857142857
I think it is right
Answer:
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
It is the last numbers I'm positive