General formula for n-th term of arithmetical progression is
a(n)=a(1)+d(n-1).
For 3d term we have
a(3)=a(1) +d(3-1), where a(3)=7
7=a(1)+2d
For 7th term we have
a(7)=a(1) +d(7-1)
a(7)=a(1) + 6d
Also, we have that the <span>seventh term is 2 more than 3 times the third term,
a(7)=3*a(3)+2= 3*7+2=21+2=23
So we have, </span>a(7)=a(1) + 6d and a(7)=23. We can write
23=a(1) + 6d.
Now we can write a system of equations
23=a(1) + 6d
<span> - (7=a(1)+2d)
</span>16 = 4d
d=4,
7=a(1)+2d
7=a(1)+2*4
a(1)=7-8=-1
a(1)= - 1
First term a(1)=-1, common difference d=4.
Sum of the 20 first terms is
S=20 * (a(1)+a(20))/2
a(1)=-1
a(n)=a(1)+d(n-1)
a(20) = -1+4(20-1)=-1+4*19=75
S=20 * (-1+75)/2=74*10=740
Sum of 20 first terms is 740.
You have to multiply 3x3 since it says 3^2 then subtract 9 from 10 you get 1. Then you have to diving 8x and 1 and you get 1/8
Answer:
arc AB = 60°
Step-by-step explanation:
The diameter splits the circle into two semi circles.
in the semicircle above the diameter, you can do 180° - 120° = 60°
so arc AB = 60°
( I'm sorry; I'm not sure how to get the answer in terms of pi. )
Answer:
(x)=3x^2−12x+16
Answer- =3x2−12x+16
Step-by-step explanation:
Hope this helps :)
-7 and 5. The product would be -35 and the sum -2.
Hope this helps
