If an is a5
and
an-1 is a4
then using your recursive formula for an arithmetic sequence
an=an-1 +d
then
a5=a4+d
now, a4 =6 and common difference "d" is d=-11
hence
a5=6 -11
6-11= -5
any questions?
Let, number of children are x and number of adult are y.
Total number of seats, T = 180.
x + y = 180 ....1)
Tickets to a 3D movie cost $12.50 for adults and $8.50 for children.
So, total amount :
8.5x + 12.5y = A
8.5x + 12.5y = 1826 ....2)
Solving equation 1) and 2) , we get :
8.5x + 12.5( 180 - x ) = 1826
8.5x - 12.5x + 2250 = 1826
-4x = -424
x = 106
y = 180 - 106 = 74
Therefore, the number of adult tickets and the number of children's tickets that were sold are 74 and 106.
Hence, this is the required solution.
Answer: 11x-3y = 32
---------------------------------------------------------------
Explanation:
The given points are
A = (-4,-2)
B = (4,4)
C = (18,-8)
First we'll use points A and C to find the slope of line AC
m = (y2-y1)/(x2-x1)
m = (-8-(-2))/(18-(-4))
m = (-8+2)/(18+4)
m = -6/22
m = -3/11
The slope of AC is -3/11
Take the negative reciprocal of this slope
Flip the fraction: -3/11 -----> -11/3
Flip the sign: -11/3 ----> +11/3 = 11/3
The slope of AC is -3/11 while the slope of any line perpendicular to AC is 11/3
Let m = 11/3 and (x,y) = (4,4) which are the coordinates of point B
Plug these values into slope intercept form and then solve for b
y = mx+b
4 = (11/3)*4+b
4 = 44/3+b
4 - 44/3 = 44/3+b-44/3
b = 4 - 44/3
b = 12/3 - 44/3
b = (12 - 44)/3
b = -32/3
Since m = 11/3 and b = -32/3, we go from this
y = mx+b
to this
y = (11/3)x-32/3
Now clear out the fractions and get the x and y variables to one side
y = (11/3)x-32/3
3y = 3*[ (11/3)x-32/3 ]
3y = 11x - 32
3y-11x = 11x-32-11x
-11x+3y = -32
-1*(-11x+3y) = -1*(-32)
11x-3y = 32
The equation of the through B that is perpendicular to AC is 11x-3y = 32 (this equation is in Ax+By = C form which is called standard form)
This is better known as the altitude through B
Answer:
12.
m∠ACB = 180° - 58° - 78° = 44°
m∠DCE = 180° - 85° - 60° = 35°
m∠BCD = 180° - 44° - 35° = 101°
13.
Base on the picture, we know that:
x° + 2x° + 3x° = 180°
6x° = 180°
x° = 180° ÷ 6 = 30°
=> m∠K = 2x° = 2 × 30° = 60°
=> m∠L = 3x° = 3 × 30° = 90°
=> m∠KML = x° = 30°
m∠LMN = 60° + 90° = 150°
