y = 10x + 5
The difference in the consecutive values of y is 10
That is 25 - 15 = 10 , 35 - 25 = 10 , 45 - 35 = 10
multiply the corresponding value of x by the difference and note what has to be added or subtracted from it to give y
x = 1 ⇒ y = (10 × 1 ) + ? = 15
x = 2 ⇒ y = (10 × 2 ) + ? = 25
x = 3 ⇒ y = (10 × 3 ) + ? = 35
x = 4 ⇒ y = (10 × 4 ) + ? = 45
In each case ? = 5
The required equation is y = 10x + 5
