Write an expression for the sequence shown below.
X Y
3 10
4 13
5 16
6 19
7 22
y changes by 3 when x changes by 1. So, the slope is 3
y = 3x+b
Now just plug in any pair of values to find b.
( 3, 10 ) , ( 4 , 13 ) , ( 5 , 16 ) , ( 6 , 19 ) , ( 7, 22 )
Change of x:
4 - 3 = 1
5 - 4 = 1
6 - 5 = 1
7 - 6 = 1
Change of y:
13 - 10 = 3
16 - 13 = 3
19 - 16 = 3
22 - 19 = 3
When x change for ∆x = 1 y is change for ∆y = 3
Slope m = ∆y / ∆x = 3 / 1 = 3
The "point-slope" form of the equation of a straight line is:
y − y1 = m ( x − x1 )
Take any point., for example ( 3, 10 ) which means x1 = 3 , y1 = 10
y − 10 = 3 ( x − 3 )
y - 10 = 3 ∙ x - 3 ∙ 3
y - 10 = 3 x - 9
Add 10 to both sides
y - 10 + 10 = 3 x - 9 + 10
y = 3 x + 1
To find the expression for the given sequence, we need to analyze the pattern or relationship between the values of X and Y. By observing the sequence, we can see that as X increases by 1, Y increases by 3.
We can express this relationship using an equation. Let's denote X as n (since X represents the position in the sequence), and Y as y (the corresponding value). Based on the observation, we can state that:
y = 3n + c
Here, c represents a constant that accounts for the initial value of Y when X is 0. To determine the value of c, we can use the first set of values in the sequence, X = 3, and Y = 10:
10 = 3(3) + c
10 = 9 + c
c = 10 - 9
c = 1
Finally, substituting the value of c into the equation, we get the expression for the given sequence:
y = 3n + 1