I believe the answer would be A.
First you want to get it to y=mx+b. to do this you have to get the y by itself on one side. 2x-5y=7 you bring -5y over and get 2x=5y+7. Then bring the 7 over and get 2x-7=5y and finally get rid of the 5 by dividing both sides by it 2x-7/5 turns into 2/5x-7/5 and 5y becomes y. Y=2/5X-7/5. Next to get the slope of a line perpendicular to another you first flip the original slope (2/5x to 5/2x) and then reverse the sign (5/2x to -5/2x). and now you have Y=-5/2X+B. To get B you must put in what you know (X is 4, Y is 3) Get 3=-5/2(4)+B and solve.
3=-5/2(4)+B to 3=-10+B. bring -10 over and get 13=B and put that in. Finally you have Y=-5/2X+13.
0.765 (100) + .06 (.0765 x 100)
76.5 + .06 (76.5)
76.5 + 4.59 = 81.09 Chris will pay $81.09
A better way ( if you don't care to know the tax just the bottom line of what it will cost) would be to do:
0.765x x 1.06 = 76.5 x 1.06 = $81.09 too.
Why the 1 in front of the .06? The one includes the price of the coat so you don't have to add the tax on after.
Think about it like this. When you buy something you pay (even with an employee
discount) for all of it (100%) + the tax (in this case, it's 6%) So you pay 106% of the cost of the item. 106% = 1.06
[1], [3] => a = 49,000/2 = 24,500 => b +c = 24,500 => c = 24,500 - b;
[2] => 25*24,500 + 20b + 15c = 1,052,000 => 20b + 15c = 1,027,500;
20b + 15*(24,500 - b) = 1,027,500 => 5b = 733,500 => b = 146,700 =>
c = - 122,200;
Answer: 693 years
Step-by-step explanation:
Expression for rate law for first order kinetics is given by:
k = rate constant
t = time taken for decomposition = 1
= Initial amount of the reactant
= amount of the reactant left =
for half life : 
Putting in the values , we get
Thus half life of this isotope, to the nearest year is 693.
