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Irina-Kira [14]
3 years ago
13

The seventh term of an arithmetic sequence is 21, and the tenth term is 126. The first term is _____..

Mathematics
2 answers:
garri49 [273]3 years ago
7 0
Pretend that the first term is 21, and the fourth term is 126 
<span>it's the same thing. </span>
<span>126 =21 +3d </span>
<span>105=3d </span>
<span>d=35 </span>
<span>21 =a1 +6(35) </span>
<span>21=a1 +210 </span>
<span>a1=-189</span>
Ivan3 years ago
7 0
a_7=21;\ a_{10}=126\\\\a_{10}-a_7=3d\\\\subtitute\\\\3d=126-21\\3d=105\ \ \ |divide\ both\ sides\ by\ 3\\d=35\\\\a_1=a_7-6d\\\\a_1=21-6\cdot35=21-210=-189\\\\Answer:\boxed{a_1=-189}
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Given A(3, 4), B(4, 3) and C(2, 1), what are the coordinates of C', the image of C under a rotation of 90 degrees about the orig
Aleks [24]

<u>Given</u>:

The coordinates of the points A, B and C are (3,4), (4,3) and (2,1)

The points are rotated 90° about the origin.

We need to determine the coordinates of the point C'.

<u>Coordinates of the point C':</u>

The general rule to rotate the point 90° about the origin is given by

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Substituting the coordinates of the point C in the above formula, we get;

(2, 1) \Rightarrow(-1, 2)

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5 0
3 years ago
A bus went halfway from a village to a city at a certain speed. Then it stopped in traffic for an hour. In order to catch up the
k0ka [10]
We have to assume that the speed before being stuck was sufficient to get to the destination on time had there been no delay. Call that speed "s" in km/h.

Since 200 km is "halfway", the total distance must be 400 km.

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400/s = 200/s + 1 + 200/(s+10) . . . .times are in hours, distances in km
200/s = 1 + 200/(s+10) . . . . . . . . . . subtract 200/s
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4 0
3 years ago
Can you help me please
Dima020 [189]

Answer:

∠1 = 48

∠2 = 132

∠4 - 132

Step-by-step explanation:

∠3 and ∠1 are vertical angles

vertical angles are congruent ( equal to each other )

So if ∠3 = 48° then ∠1 also = 48°

∠3 and ∠4 are supplementary angles

supplementary angles add up to equal 180°

Hence, ∠3 + ∠4 = 180

48 + ∠4 = 180

180 - 48 = 132

Hence, ∠4 = 132

∠4 and ∠2 are vertical angles

Like stated previously vertical angles are congruent

Hence, ∠2 = 132

4 0
3 years ago
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liraira [26]
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3 years ago
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What's the answer to R+5=-13?
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The answer is: R=-18
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3 years ago
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