Đáp án:
`=52x`
Giải thích các bước giải:
`6x(3x+7)-2x(9x-5)`
`=6x.3x+6x.7-2x.9x+2x.5`
`=18x^2+42x-18x^2+10x`
`=(18x^2-18x^2)+(42x+10x)`
`=0+52x`
$52x$
$6x(3x+7)-2x(9x-5)\\=6.3.x.x+7.6.x-2.9.x.x+2.5.x\\= 18x^2+42x-18x^2+10x= 52x$
I. Use the words and phrases to write a passage. 1. In/ 1970s, skateboarding suddenly/ become very popular. 2. At first, skateboarders/ move slowly/ flat, smooth areas. 3. Then they/ begin/ ride quickly. This/ be called “freestyle” skateboarding. 4. Soon they/ be skateboarding skillfully up ramps/ doing tricks in the air. 5. This/ be called “ramp” skateboarding. Then they/ start skateboarding/ doing tricks/ the street. 6. This/ be “street-style” skateboarding - a combination of freestyle/ ramp. 7. For this, the skateboarders/ need protective clothing/ as knee and elbow pads/ helmets. This/ allow them/ skateboard safely. 8. Today skateboarding is still/ very popular sport, and there/ are lots of competitions.
cho tam giác abc, trung tuyến ad, be, cf. trong đó ad vuông góc be, ad=3; be=4. a) vẽ k sao cho d là trung điểm ek. cm afkd là hình bình hành b) tính cf giúp mình với!!!!!!!!!!1
Calli: Khi Anh Qua Thung Nũng ~~
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