<span>This is an arithmetic progression, i.e. 16,18,20,22,24,26,28.......... where 16 is the number of people seats in 1st row, 18 seats in second row, 20 seats in third row and so on. The Total number of seats in 20 rows = n/2{2a+(n-1)d}. Here, d = 2 , n =20, a = 16. Thus, Sum = 10 {32+ 19*2} = 10 {70} = 700 seats in total. </span>
Answer:
The integers are 4 and 7 or -2 and 1.
Step-by-step explanation:
You can make a system of equations with the description of the two integers.
1. x = y + 3
2. 2x + 2 = y^2
The simplest and the fastest way to solve this system in this case is substitution. You can substitute x for y + 3 in the second equation.
1. x = y + 3
2. 2(y + 3) + 2 = y^2
Now simplify and solve the second one. For convenience, I will just disregard the first equation for now.
2y + 6 + 2 = y^2
y^2 - 2y - 8 = 0
You can factor this equation to solve for y.
(y - 4) (y + 2) = 0
y = 4, y = -2
Now we can substitute the value of y for x in the first equation.
x = 7, x = 1
Answer:
x=0.00784
Step-by-step explanation:
Hello,
y=2^(-x)
y=2^(2x)+3
==>2^(2x)+3=1/2^x
==>2^(3x)+3*2^x-1=0 (1)
Let's assume u=2^x
(1)==>u^3+3*u-1=0
which as 3 roots
u=0.322185354626 or
u = -0.161092677313 + i1.754380959784 or
u = -0.161092677313 - i1.754380959784.
Let's take the real solution
0.322185354626=2^x
==>x=ln(0.322185354626) / ln(2)
x=-1,6340371790199...
an other way is
f(x)=2^(3x)+3*2^x-1
f(-2)=1/64+3/4-1=-15/64 <0
f(-1)=1/8+1-1=1/8>0
==> there is a solution betheen -2<x<-1