Question

（2x平方-二分之一+3x）-4（x-x平方+二分之一）

Answer 1

（2x²-1/2+3x）-4（x-x²+1/2）
=2x²-1/2+3x-4x+4x²-2
=6x²-x-5/2

Answer 2

√18除以√8
=√(18÷8)
=√(9/4)
=3/2

√0.4乘以√3.6
=√(0.4×3.6)
=√1.44
=√1.2²
=1.2

√3分之2乘以√8分之27=
=√(2/3×8/27)
=√(16/81)
=4/9

√2除以3√40
=(1/3)√(2÷40)
=(1/3)√(1/20)
=(1/3)√(5/100)
=(1/3)(√5)/10
=(√5)/30