6(3a-2)+5a=57
18a-12+5a=57
23a-12=57
23a=69
a=3
Answer:
X=2
Step-by-step explanation:
Ratios
4:x = 24:12
24:12 reduced is 2:1
Therefore we can see x must be half of 4.
So the answer is 2
Hope this helps! :)
pls mark brainiest
20 percent of the discount minus 5 percent sales tax equals to 15 percent.
know calculate the 15 percentage out of 78,12 so x on 78,12 equals to 20 on 100 so 78,12 equals to 100 percent and x equals to 15 percent so 78,12 times 15 divided by 100 is 15 percent or the number you found discount and and sales tax combined know you substact 15 percent out of your original price.
If 
is the amount of strontium-90 present in the area in year 
, and it decays at a rate of 2.5% per year, then
Let 
be the starting amount immediately after the nuclear reactor explodes. Then
or simply
So that after 50 years, the amount of strontium-90 that remains is approximately
or about 28% of the original amount.
We can confirm this another way; recall the exponential decay formula,
where is measured in years. We're told that 2.5% of the starting amount 
decays after 1 year, so that
Then after 50 years, we have
