Answer:
21/45
Step-by-step explanation:
You make the denominator the same and u also multiply the top too and u subtract and thats how u get the answer
If you put brackets around (2+1), your method of working is:
1) 15-4*(2+1)=3
2) 15-4*3=3
3) 15-12=3
You don't need any more brackets, as the BIDMAS (brackets, Indices, division, multiplication, addition, subtraction) rule does the rest of the job for you.
The answer is therefore: 15-4*(2+1)=3
