Question

Nelson Mandela was a South African politician known for fighting racism and inequality. He was president of South Africa until he stepped down in the year 199919991999. Let xxx represent any year. Write an inequality in terms of xxx and 199919991999 that is true only for values of xxx that represent years after the year that Nelson Mandela stepped down from his presidency.

Answer 1

One possible inequality would be

1999-x<0.

If you subtract any year after he stepped down from 1999, the year he stepped down, the result will be a negative number.

Answer 2

We know Nelson was president in the year 1999. If x, represents any year at all then we have to write an equality to represent years after the year that Nelson stepped down from the presidency.

1999-x<0

Because 1999 has to be less than the value it is up for. Any year after 1999 would be greater than 1999. This has to be a negative number because if you subtract any year after he stepped down the result will have to be negative, because the year will be after 1999. Hope this helps!