book Maths Puzzle Numerical Ability

I need major help!!

4 over 4-3 times 3 squared

Read Solution (Total 0)

book Other Question

Need to solve the following by addition/elimination method:
1.8x - 2y = 0.9
0.04x + 0.18x = 0.15 (Multiplied both lines by 100 to get rid of decimals)

180x - 200y = 90
(-4 what is scientific notation?