9514 1404 393
Answer:
(x, y) = (3.5, -4)
Step-by-step explanation:
Elimination is easiest if one of the coefficients of a variable is a multiple of the other coefficient of the variable. Here, we have x-coefficients of 4 and 8, so it will be easiest to eliminate x.
Subtract the second equation from 2 times the first.
2(4x +7y) -(8x +5y) = 2(-14) -(8)
9y = -36 . . . . . simplify
y = -4 . . . . . . . divide by 9
4x +7(-4) = -14 . . . . substitute for y in the first equation
4x = 14 . . . . . . . add 28
x = 3.5 . . . . divide by 4
The solution is (x, y) = (3.5, -4).
A(t) = Ao*e^(-rt)
-rt = ln [ A(t)/ Ao]
t = - ln [ A(t)/ Ao] / r
r= 0.0124% = 0.0124/100 = 0.000124
A(t)/A0 = 10% = 10/100 = 0.1
Now substitute
t = - ln [0.1] / 0.000124 = 2.3025851 / 0.000124 = 18,569 years
Your result will depend on how you round ln(0.1).
Answer:
a = 133 degrees
b = 78 degrees
Step-by-step explanation:
the top and bottom lines are parallel.
the two sidelines are lines that intercept the top and bottom lines.
as they intercept parallel lines, they actually must have the same angles with them.
so, the 47 degrees inner angle at the bottom line, must be also somewhere at the interception point with the top line. and right, it must be now mirrored the outward angle at the top line. and that means a (the inward angle at the top line) is also the outward angle at the bottom line.
the sum of inward and outward angles at a point must always be 180 degrees.
so, the outward angle of 47 = the inward angle a =
= 180 - 47 = 133 degrees.
similar in the other side.
102 is the inward angle.
the outward angle of that is 180 - 102 = 78 degrees.
and that is also the inward angle b.
b = 78 degrees
-58.
To get this, first use the equation -b/2a. This will first find the maximum. After you find the maximum, input the answer into the original equation and solve for the minimum.
Hope this helps!
