Answer:
[tex]x_2 - x_1 = 1[/tex] gives [tex]y_2 - y_1 = 4[/tex]
Step-by-step explanation:
Given
[tex]y = 4x[/tex]
[tex](x_1,x_2) = (x,x+1)[/tex]
Required
Show that the y values increases by 4 for [tex]x_2 - x_1 = 1[/tex]
We have:
[tex]y = 4x[/tex]
For [tex]x_1 = x[/tex]
[tex]y_1 = 4x_1[/tex]
Substitute [tex]x_1 = x[/tex]
[tex]y_1 = 4x[/tex]
For [tex]x_2 = x + 1[/tex]
[tex]y_2 = 4x_2[/tex]
Substitute [tex]x_2 = x + 1[/tex]
[tex]y_2 = 4(x+1)[/tex]
[tex]y_2 = 4x+4[/tex]
So, we have:
[tex]y_2 = 4x+4[/tex]
[tex]y_1 = 4x[/tex]
Subtract [tex]y_1[/tex] from [tex]y_2[/tex]
[tex]y_2 - y_1 = 4x + 4 - 4x[/tex]
Collect like terms
[tex]y_2 - y_1 = 4x - 4x+ 4[/tex]
[tex]y_2 - y_1 = 4[/tex]
Hence:
[tex]x_2 - x_1 = 1[/tex] gives [tex]y_2 - y_1 = 4[/tex]
i.e. an increment of 4