Hey there!
400g^2 - 0.9 ÷ g
= 400(0.5)^2 - 0.9 ÷ 0.5
0.5^2 = 0.5 * 0.5 = 0.25
= 400(0.25) - 0.9 ÷ 0.5
400(0.25) = 100
= 100 - 0.9 ÷ 0.5
0.9 ÷ 0.5 = 1.8
100 - 1.8 = 98.2
Therefore, your answer is: 98.2
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)