Answer: 40 million
Step-by-step explanation:
Number of families that had TVs in their home in 1980s = 60 million
Number of families that had TVs in their home in 2015 = 100 million
To calculate the increase in TVs that were there in 2015, we subtract the number of families that had TVs in their home in 1980s which was 60 million from the number of families that had TVs in their home in 2015 which was 100 million. This can be expressed as:
= 100 million - 60 million
= 40 million
The formula to find any term of an an arithmetic sequence is given by
=
=(n-1)d,
where we have first term
=8,
and d which is the common difference , and n is the term we need to find (in our case is 20)
the difference d=3, as you see each number is the previous minus 3
for S20=8+(20-1)*(-3)=8+(19)*(-3)=8-57=-49
S20=-49, this the 20th term
Answer:
Step-by-step explanation:
USE FOIL method
(x +6)(x + 2) = x*x + x*2 +6*x +2*6
=x² + 2x + 6x + 12 {Combine like terms}
= x² + 8x + 12
(x+ 7)(x + 2) = x*x+ x*2 +7*x + 7*2
= x² +2x+ 7x + 14
= x² + 9x + 14
(x+1)*(x +7) = x*x + x *7 + 1*x + 1*7
=x² + 7x +x + 7
=x² + 8x + 7
Cross multiply,
5*(3x+1) = x² + 9x + 14
5*3x + 5*1 = x² + 9x + 14
15x + 5 = x² + 9x + 14
x² + 9x + 14 - 5x - 5 = 0
x² + 9x - 5x + 14 - 5 = 0
Combine like terms
x² + 4x + 9 = 0
a = 1 ; b = 4 ; c = 9
D = b² - 4ac
= 4² - 4*1*9
= 16 - 36
= -20
= 20i² {i² = -1}
√D = √20i² =
F(g(3))
find g(3)
g(3)=3^2+1=9+1=10
f(g(3))=f(10)
f(10)=2(10)+3=20+3=23
f(g(3))=23