A: For this equation, follow BIDMAS, so first multiply each value inside the brackets by 4:
= 43x + 42 - 2 ("*" meaning multiply)
= 12x + 8 - 2
= 12x +6
And I think you're done.
B: For this you need to put in brackets, so find the highest common factor of the values and put it outside the brackets:
Both 20 and 16 are divisible by 4 so
4(5b - 4)
So that when you multiply out the brackets you get back to 20b - 16.
Hope his helps.
