496 lượt thi
5 câu hỏi
45 phút
Câu 1:
2514x2y;1421xy5
Nhân tử phụ:
42x2y5:14x2y=3y442x2y5:21xy5=2x
Quy đồng:
2514x2y=25.3y442x2y5=75y442x2y51421xy5=14.2x42x2y5=28x42x2y5
Câu 2:
4x−42xx+3;x−33xx−3; MTC:6xx+3x−3
6xx+3x−3:2xx+3=3x−36xx+3x−3:3xx−3=2x+3
4x−42xx+3=4x−4.3x−36xx+3x−3=12x2−48x+366xx+3x−3x−33xx−3=x−3.2.x+33xx−3.2x+3=2x2−186xx+3x−3
Câu 3:
2xx+23;x−22xx+22, MTC: 2xx+23
2xx+23:x+23=2x2xx+23:2xx+22=x+2
2xx+23=2x.2x2xx+23=4x22xx+23x−22xx+22=x−2x+22xx+22=x2−42xx+22
Câu 4:
5x2x3+6x2+12x+8;4x2+4x+4;32x+4
Hay 5x2x+23;4x+22;32x+2. MTC:2x+23
2x+23:x+23=22x+23:x+22=2x+22x+23:2x+2=x+22
5x2x+23=5x2.22x+23=10x22x+234x+22=4.2x+22x+23=8x+22x+2332x+2=3x+222x+23
Câu 5:
Q=x10−x8+x7+x6+x5+x4−x3−x2+1x30+x24+x18+x12+x6+1=x10−x8+x6−x7−x5+x3+x4−x2+1x18x12+x6+1+x12+x6+1=x4−x2+1x6−x3+1x12+x6+1x18+1=x4−x2+1x6−x3+1x12+2x6+1−x6x6+1x12−x6+1
=x4−x2+1x6−x3+1x6+1−x6x2+1x4−x2+1x12−x6+1
=x6−x3+1x6+x3+1x6−x3+1x2+1x12−x6+1=1x6+x3+1x2+1x12−x6+1
7 câu hỏi
9 câu hỏi