Answer:
a = 3
b = 2
c = 0
d = -4
Step-by-step explanation:
Form 4 equations and solve simultaneously
28 = a(2)³ + b(2)² + c(2) + d
28 = 8a + 4b + 2c + d (1)
-5 = -a + b - c + d (2)
220 = 64a + 16b + 4c + d (3)
-20 = -8a + 4b - 2c + d (4)
(1) + (4)
28 = 8a + 4b + 2c + d
-20 = -8a + 4b - 2c + d
8 = 8b + 2d
d = 4 - 4b
Equation (2)
c = -a + b + d + 5
c = -a + b + 4 - 4b+ 5
c = -a - 3b + 9
28 = 8a + 4b + 2c + d (1)
28 = 8a + 4b + 2(-a - 3b + 9) + 4 - 4b
28 = 6a - 6b + 22
6a - 6b = 6
a - b = 1
a = b + 1
220 = 64a + 16b + 4c + d (3)
220 = 64(b + 1) + 16b + 4(-b - 1 - 3b + 9) + 4 - 4b
220 = 60b + 100
60b = 120
b = 2
a = 2 + 1
a = 3
c = -3 - 3(2) + 9
c = 0
d = 4 - 4(2)
d = -4
so basically what you would have to do is set up your numbers. it would look something like this. 68
× 49
-------------
and would then multiply 9 by 8, 9 by 6. put it down below the line while making sure to carry the numbers if need be. then do the same with the 4 times 8, and 4 by 6.
The price decreased by 40%.
Answer:
80 minutes
Step-by-step explanation:
Rate and Time are inverses of each other
First,
Elise Time = 12
and
Katherine Time = 2 * 12 = 24
Their rates would be (inverses):
Elise Rate = 1/12
Katherine Rate = 1/24
Together their rate is 1/12 + 1/24 = 3/24
Now, the inverse of this rate would be the time it takes to complete 1 bag together, that is:
(3/24) ^ -1 = 24/3 = 8 minutes
So, 10 bags would take them:
8 * 10 = 80 minutes
Answer:
y = -5x/4 - 8
Step-by-step explanation:
Two lines that are perpendicular have slopes that are opposite reciprocals.
Since the slope of the given line is 4/5, the opposite reciprocal of that is -5/4. So the equation has a slope of -5/4.
Since we know the coordinate of a point of the other equation, we can plug that into the point-slope form equation y - y1 = m(x - x1):
y - 2 = -5/4(x-(-8))
Simplify:
y - 2 = -5/4(x+8)
y - 2 = -5x/4 - 10
So the equation in slope-intercept form is:
y = -5x/4 - 8
