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3 years ago

(please help and explain) will mark brainliest!!

Mathematics

1 answer:

9966 [12]3 years ago

7 0

Answer:

x = 40

Step-by-step explanation:

Angles SRT and STR are congruent, so they have the same measure.

The measure of <SRT is 20, so the measure of <STR is also 20.

Angles STR and STU form a linear pair. Two angles that form a linear pair are supplementary, so their measures add up to 180.

m<STR + m<STU = 180

20 + 4x = 180

4x = 160

x = 40

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1) Greaters sold 30 milkshakes last week. 20%. of the milkshakes had whipped cream on them. How many shakes had whipped cream? A

Semenov [28]

Answer:

plz vote me brainliest

Step-by-step explanation:

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2 years ago

Use variation of parameters to find a general solution to the differential equation given that the functions y1 and y2 are linea

Aleks [24]

Recall that variation of parameters is used to solve second-order ODEs of the form

y''(t) + p(t) y'(t) + q(t) y(t) = f(t)

so the first thing you need to do is divide both sides of your equation by t :

y'' + (2t - 1)/t y' - 2/t y = 7t

You're looking for a solution of the form

$y=y_1u_1+y_2u_2$

where

$u_1(t)=\displaystyle-\int\frac{y_2(t)f(t)}{W(y_1,y_2)}\,\mathrm dt$

$u_2(t)=\displaystyle\int\frac{y_1(t)f(t)}{W(y_1,y_2)}\,\mathrm dt$

and W denotes the Wronskian determinant.

Compute the Wronskian:

$W(y_1,y_2) = W\left(2t-1,e^{-2t}\right) = \begin{vmatrix}2t-1&e^{-2t}\\2&-2e^{-2t}\end{vmatrix} = -4te^{-2t}$

Then

$u_1=\displaystyle-\int\frac{7te^{-2t}}{-4te^{-2t}}\,\mathrm dt=\frac74\int\mathrm dt = \frac74t$

$u_2=\displaystyle\int\frac{7t(2t-1)}{-4te^{-2t}}\,\mathrm dt=-\frac74\int(2t-1)e^{2t}\,\mathrm dt=-\frac74(t-1)e^{2t}$

The general solution to the ODE is

$y = C_1(2t-1) + C_2e^{-2t} + \dfrac74t(2t-1) - \dfrac74(t-1)e^{2t}e^{-2t}$

which simplifies somewhat to

$\boxed{y = C_1(2t-1) + C_2e^{-2t} + \dfrac74(2t^2-2t+1)}$

4 0

3 years ago

Factorise fully − z − 9

NeX [460]

Answer:

Yes

Step-by-step explanation:

Question

4 0

2 years ago

Jon recently drove to visit his parents who live 280 miles away. On his way there his average speed was 9 miles per hour faster

Luba_88 [7]

Answer:

11 mph and 20 mph

Step-by-step explanation:

Represent his average speed going by r1 and his average speed returning by r2. We know that r1 = r2 + 9.

Recall that distance = rate times time, so time = distance / rate.

Time spent going was (280 mi) / r1, or (280 mi) / (r2 + 9 mph).

Time spend returning was (280 mi) / r2.

The total time was 14 hrs, so (280 mi) / (r2 + 9 mph) + (280 mi) / r2 = 14 hrs

Note that there is only one variable here: r2. Find r2, and then from r2, find r1:

Dividing all 3 terms by 14 hrs yields:

20 20

---------- + ----------- = 1

r2 + 9 r2

The LCD here is r2(r2 + 9). Thus, we have:

20r2 (r2 + 9)(r2)

------------------- = 1 or ------------------

(r2 + 9)(r2) (r2 + 9)(r2)

Then 20(r2) = (r2)^2 + 9(r2). This is reducible by dividing all terms by r2:

20 = r2 + 9, or 11 = r2. Then r1 = 11 + 9, or 20.

The two rates were 11 mph and 20 mph.

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3 years ago

Sum of exterior angles in a polygon?

soldi70 [24.7K]

Answer:

360

Step-by-step explanation:

The exterior angles always add up to 360 in a polygon because it's the sum of all the vertexes which would make a circle.

8 0

3 years ago