Divide by 7.
... |-7x -3| = 3
Unfold to two equations.
... -3 = -7x -3 . . . . . the content of the absolute value is negative
... 0 = -7x . . . . . . . . add 3
... 0 = x . . . . . . . . . . divide by -7
and
... 3 = -7x -3 . . . . . . the content of the absolute value is positive
... 6 = -7x . . . . . . . . add 3
... -6/7 = x . . . . . . . . divide by -7
The solutions are ...
... x = -6/7 or x = 0
_____
Many graphing programs will happily tell you the locations of x- and y-intercepts, so it is convenient to rewrite the equation so its value is zero at the solution points. We can do that by subtracting the right side constant to get ...
... 7|-7x -3| -21 = 0
(126) times (1/2 to the x/11 power) = 15% times 126
(1/2) to the x/11 power = 0.15
Take the log of both sides :
(x/11) times log(1/2) = log(0.15)
Multiply both sides by 11 :
'x' times log(1/2) = 11 x log(0.15)
Divide both sides by " log(1/2) " :
x = 11 x log(0.15)/log(1/2) = <em><u>30.107 years</u></em> (rounded)
That's the time it takes for <em><u>any-size</u></em> sample of this substance
to decay to 15% of its original size.
The answer is K= 7 because
-5-7=-12
.67
Step-by-step explanation6 divided by 9