中四數學 MC.

1.D
5(x+3)+1
=5x+16

2.A
4/(x²+2x-3) - 3/(x²+x-2)
=4/[(x+3)(x-1)] - 3/[(x+2)(x-1)]
=[4(x+2) - 3(x+3)]/[(x+3)(x+2)(x-1)]
=[4x+8 - 3x-9]/[(x+3)(x+2)(x-1)]
=[x-1]/[(x+3)(x+2)(x-1)]
=1/[(x+3)(x+2)]

3.B

4.A

1
f(x)=(5x+1)Q(x)
f(x+3)=[5(x+3)+1]Q(x+3)
f(x+3)=(5x+15+1)Q(x+3)
f(x+3)=(5x+16)Q(x+3)
ans is D

2
4/(x^2 +2x -3) -3/(x^2 +x-2)
=4/[(x-1)(x+3)] -3/[(x-1)(x+2)]
=[4(x+2)-3(x+3)]/[(x-1)(x+2)(x+3)]
=(4x+8-3x-9)/[(x-1)(x+2)(x+3)]
=(x-1)/[(x-1)(x+2)(x+3)]
=1/[(x+2)(x+3)]
ans is A

3
ans is C

4
b>0>k
ans is A

相片連結好像有問題？