Step 6 Objective

Substitute integers into simple formulae.


Probing questions

When you substitute x = –1 into the formula y = 5x – 2 you get –7. Can you make up some more formulae that also give y = –7 when x = –1 is substituted?

When you substitute a = 2 and b = 7 into t = ab + 2a you get 18. Can you make up some more formulae that also give t = 18 when a = 2 and b = 7 are substituted?

p = 4a² and p = (4a

Are these two formulae the same or different?

When? Why?