Question

What is the first term of an AP, whose third term is 440 and the comman difference -20?

Answer 1

Hello !!

For answer this question, you only need make use of this formula.

An = A1 + (n - 1) × d

Now, you put the informations of the statement in the formula and obtain the result.

An = A1 + (n - 1) × d

440 = A1 + (3 - 1) × (-20)

440 = A1 + 2 × (-20)

440 = A1 + (-40)

A1 + (-40) = 440

A1 - 40 = 440

A1 = 440 + 40

A1 = 480

Final result : 480 is the first term.

I hope I have collaborated !