Answer:
Below in bold
Step-by-step explanation:
The sequence is:
3, x, y, 18
If this is an A P then
x - 3 = y - x
2x - y = 3 (A) and
y - x = 18 - y
2y - x = 18 (B)
Multiply (A) by 2:
4x - 2y = 6 (C)
Adding B and C:
3x = 24
x = 8.
and
2y - 8 = 18
2y = 26
y = 13.
So x = 8 and y = 13.
b) ar + ar^2 = 6ar^3 where a = first term and r = common ratio
Divide by a:
r + r^2 = 6r^3
6r^3 - r^2 - r = 0
r(6r^2 - r - 1) = 0
r(3r + 1)(2r - 1) = 0
So the 2 possible values of r
= -1/3 and 1/2.
i) The common ratio is positive so it must be 1/2.
Second term ar = 8
1/2 a = 8
a = 16.
So the first 6 terms are:
16, 8, 4, 2, 1, 1/2.
2x-8y////2r+5+3r-s+11=5r+16-s////-7x+7
Answer: 45
Step-by-step explanation:
60 x .75. = 45
4x - 5y = -3 ⇒ 1st equation
2x + 3z = 4 ⇒ 2nd equation
3y - z = 8 ⇒ 3rd equation
find the value of z.
3y - z = 8
- z = 8 - 3y
z = (8 - 3y) / -1
z = -8 + 3y
Substitute z with its value in the 2nd equation:
2x + 3z = 4
2x + 3(-8 + 3y) = 4
2x - 24 + 9y = 4
2x + 9y = 4 + 24
2x + 9y = 28
find value of x
2x + 9y = 28
2x = 28 - 9y
x = (28 - 9y)/2
x = 14 - 9y/2
Substitute the value of x in 1st equation
4x - 5y = -3
4(14-9y/2) - 5y = -3
56 - 36y/2 - 5y = -3
- 36y/2 - 5y = -3 - 56
- 36y/2 - 5y = - 59
2(-36y/2 - 5y) = 2(-59)
-36y - 10y = -118
-46y = -118
-46y/-46 = -118/-46
y = 2 26/46
y = 2 13/23
x = 14 - 9y/2
x = 14 - 9 (2 13/23) /2
x = 14 - 9 (59/23) / 2
x = 14 - 531/23 / 2
x = 14 - 531/23 * 1/2
x = 14 - 531/23*2
x = 14 - 531/46
x = (14*46/46) - 531/46
x = 644/46 - 531/46
x = (644-531)/46
x = 113/46
x = 2 21/46
z = -8 + 3y
z = -8 + 3(2 13/23)
z = -8 + 3(59/23)
z = -8 + 177/23
z = (-8*23/23) + 177/23
z = -184/23 + 177/23
z = (-184 + 177)/23
z = -7/23
x = 2 21/46 ; y = 2 13/23 ; z = -7/23
4x - 5y = -3
4(113/46) - 5(59/23) = -3
452/46 - 295/23 = -3
9.826 - 12.826 = -3
-3 = -3
2x + 3z = 4
2(113/46) + 3(-7/23) = 4
226/46 - 21/23 = 4
4.913 - 0.913 = 4
4 = 4
3y - z = 8
3(59/23) - (-7/23) = 8
177/23 + 7/23 = 8
7.696 + 0.304 = 8
8 = 8
