b=3
I found this out by subtracting and adding on both sides.
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
12. On addition, you can just combine like terms.
2v^3+(-v^3)=v^3
-v+v cancels each other out
8+(-3)=5
So you have v^3+5
14 On subtraction, you have to remember to distribute the negative sign so after you do that you have:
4h^3+3h+1+5h^3-6h+2
Then you can combine like terms
4h^3+5h^3=9h^3
3h-6h=-3h
1+2=3
So you end up with:
9h^3-3h+3
Hope that helps and feel free to ask any questions.
Answer:
248
Step-by-step explanation:
130, is the answer.. so here's me having to come back and to explain,because this questions is SO hard.
They ask to round to the ten.
128
^This is ten, so we look to our right which is eight, is higher than 5. 5 is counted as higher. So 8 is over five and if we round 28, it's 30.
WOW, fascinating.
Thanks Brainly's "monitors" such help. -_-
