1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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}
You might be interested in
Name the correct angles 5 and 7
Alex787 [66]

Answer:

Acute angle.

Right angle.

Obtuse angle.

Straight angle.

Reflex angle

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
Which of the following is an equation of a line parallel to the equation y = 1x +1? 2 O A. y = -2x-5 O B. y = 2x-5 2. C. y=-1X-5
Alex777 [14]

Answer:  B. y = 2x-5  is your answer hope this helped

plz make brainly

Step-by-step explanation:

4 0
2 years ago
Please help me with this question
boyakko [2]

Answer:

0.7999989281

Step-by-step explanation:

x1 = cos^-1 (3/5)

x1= 53.13°

sin(53.13) = 0.7999989281

5 0
3 years ago
6 1⁄3 + 7 1⁄4 – 2 1⁄2 =
Korvikt [17]

Answer:

11 1/12

Step-by-step explanation:

6 1/3 = 19/3

7 1/4 = 29/4

2 1/2 = 5/2

19/3 + 29/4 - 5/2


We must find the LCM of 3, 4, and 2. This happens to be 12

3*4 = 12

4*3 = 12

2*6 = 12

Multiply each fraction by the factor that'll get it to 12.


19/3 * 4/4 = 76/12

29/4 * 3/3 = 87/12

5/2 * 6/6 = 30/12

Now go through the problem


76/12 + 87/12 - 30/12

76 + 87 = 163

163/12 - 30/12

163 - 30 = 133

133/12

Simplify

133/12 = 11.0833... or 11 1/12


Hope this helps.

6 0
3 years ago
Find the missing angle.
sineoko [7]

Answer:

121

Step-by-step explanation:

31+90 = 121

180 - 121 = 59

180 - 59 = 121

6 0
2 years ago
Other questions:
  • Kris has two choices for a part-time job after school. Kris could make $10 per hour entering data for a local company, but none
    6·2 answers
  • CNNBC recently reported that the mean annual cost of auto insurance is 954 dollars. Assume the standard deviation is 234 dollars
    13·1 answer
  • W much a quantity changes
    11·1 answer
  • Help would be really nice here just a bit lost
    10·1 answer
  • If $12.000 is invested in an account in which the interest earned is continuously
    9·1 answer
  • A man invested 800.00in a bank at a simple interest rate of 5% per annum .Find his total amou year​
    9·1 answer
  • Can some help me plz
    15·1 answer
  • The perimeter of a rectangle is 8x+10.if the length is 2x+8 what is the width?
    6·2 answers
  • What is the equation of the line that passes through the point
    10·1 answer
  • Samuel is running a 3-mile race. He would like to finish the race in under 33 minutes. He has already run for 10.5 minutes.
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!