The partial fraction expansion takes the form
-6<em>x</em>/((<em>x</em> + 2) (<em>x</em> + 8)) = <em>a</em>/(<em>x</em> + 2) + <em>b</em>/(<em>x</em> + 8)
Both factors in the denominator are linear, so the numerators in the corresponding partial fractions have degree 1 - 1 = 0 and are thus constants.
Combine the fractions on the right side into one with a common denominator, then set the numerators on both sides of the equation equal to each other:
-6<em>x</em> = <em>a</em> (<em>x</em> + 8) + <em>b</em> (<em>x</em> + 2)
Expand the right side and collect terms by powers of <em>x</em> :
-6<em>x</em> = (<em>a</em> + <em>b</em>) <em>x</em> + (8<em>a</em> + 2<em>b</em>)
It follows that
<em>a</em> + <em>b</em> = -6 and 8<em>a</em> + 2<em>b</em> = 0
==> <em>a</em> = -2 and <em>b</em> = 8
So we end up with
-6<em>x</em>/((<em>x</em> + 2) (<em>x</em> + 8)) = -2/(<em>x</em> + 2) + 8/(<em>x</em> + 8)
To find these two lets convert this into slope-intercept form:
-7x + 7y = -17
7y = 7x -17
y = x - 17/7
So, the slope is 1 and the y-intercept is -17/7
Hope this helps!
Answer:
No, as a scalene triangle's sides are are different, while an equilateral's sides are all the same.
Hope that helps, :)
Answer:
1a) 210
1b) 0.18
2) 17.7 will fit (> 17)
3) 515 cm^2
Step-by-step explanation:
1a) The sample of 25 is exactly 1/30 of the population of 750, so the number of orange cakes in the population will be 30 times the number in the sample.
The total number of orange cakes made on Monday is 30·7 = 210.
__
1b) The lowest number that will round to 5 is 4.5. The lowest probability that a cake is an orange cake is ...
4.5/25 = 18/100 = 0.18
The lower bound on the probability that the cake is orange is 0.18.
____
2) The working shown is partly correct.
The possible error in the box dimension is 1/2 cm, so the box may be as short as 28 -1/2 cm = 27.5 cm.
The possible error in the disc case dimension is 1/2 mm = 0.05 cm, so the case may be as thick as 1.5 +.05 = 1.55 cm.
The minimum number discs that will fit in the case is (27.5 cm)/(1.55 cm) = 17.7. Thus, 17 cases will definitely fit in the box.
____
3) The shaded area will be the largest when the outside rectangle is the largest and the inside rectangle is the smallest. Errors in dimensions can be as much as 1/2 cm, so the Outside rectangle can be 42.5 cm by 21.5 cm. The inside rectangle can be as small as 27.5 cm by 14.5 cm.
Then the shaded area can be as large as ...
(42.5)(21.5) -(27.5)(14.5) = 515 . . . . cm^2
