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3 years ago

50+25=75 25+25=50 25=

Mathematics

1 answer:

Vesna [10]3 years ago

4 0

50+25+75+25+25+50+25=275

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7x-8y=11 8x-7y=7 solve using substitution

lord [1]

Answer:

(x,y)=(37,31)

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3 years ago

A train travels 190 km in 3.0 hours and then 120 km in 2.0 hours. What is its average speed?

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The average speed it 310

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3 years ago

I neeeeeedddd help pls

Gre4nikov [31]

I CAN HELP YOUUUUUUUUUUUUUUUUUU!!!!!!!!!!!!!!!!!!1

lets distribute 7(x+3)

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yay :)

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3 years ago

Read 2 more answers

If S_1=1,S_2=8 and S_n=S_n-1+2S_n-2 whenever n≥2. Show that S_n=3⋅2n−1+2(−1)n for all n≥1.

Snezhnost [94]

You can try to show this by induction:

• According to the given closed form, we have $S_1=3\times2^{1-1}+2(-1)^1=3-2=1$ , which agrees with the initial value S₁ = 1.

• Assume the closed form is correct for all n up to n = k. In particular, we assume

$S_{k-1}=3\times2^{(k-1)-1}+2(-1)^{k-1}=3\times2^{k-2}+2(-1)^{k-1}$

and

$S_k=3\times2^{k-1}+2(-1)^k$

We want to then use this assumption to show the closed form is correct for n = k + 1, or

$S_{k+1}=3\times2^{(k+1)-1}+2(-1)^{k+1}=3\times2^k+2(-1)^{k+1}$

From the given recurrence, we know

$S_{k+1}=S_k+2S_{k-1}$

so that

$S_{k+1}=3\times2^{k-1}+2(-1)^k + 2\left(3\times2^{k-2}+2(-1)^{k-1}\right)$

$S_{k+1}=3\times2^{k-1}+2(-1)^k + 3\times2^{k-1}+4(-1)^{k-1}$

$S_{k+1}=2\times3\times2^{k-1}+(-1)^k\left(2+4(-1)^{-1}\right)$

$S_{k+1}=3\times2^k-2(-1)^k$

$S_{k+1}=3\times2^k+2(-1)(-1)^k$

$\boxed{S_{k+1}=3\times2^k+2(-1)^{k+1}}$

which is what we needed. QED

6 0

3 years ago

Plz help me I need because it’s one of my last assignments for school

Brums [2.3K]

Step-by-step explanation:

straight line = 180 degree

example

1) 2w - 24 + 2w - 40 = 180

4w = 180 + 24 + 40

4w = 244

w = 244/4

.......

2) 13n - 11 +(-9 + 12n)

13n - 11 -9 + 12n = 180

25n -20 = 180

25n = 180 + 20

25n = 200

n = 200/25

.........

8 0

3 years ago