$7,2x13+3,6x71+3,6+7,2\\=7,2x(13+1)+3,6x(71+1)\\=7,2x14+3,6x72\\=7,2x14+7,2x3,6x10\\=7,2x14+7,2x36\\=7,2x(14+36)\\=7,2x50\\=360$

`5/7xx4=20/7`

`4/3-1=4/3-3/3=1/3`

`4/7+5/21=12/21+5/21=17/21`

`7/2:3=7/2xx1/3=7/6`

`7800:100+56xx14`

`=78+784`

`=862`

`x-5/6=1/2`

`x=1/2+5/6`

`x=3/6+5/6`

`x=8/6`

`x=4/3`

$a)\sqrt{(2,5)^2}\\=|2,5|=2,5\\b)\sqrt{\dfrac{64}{25}}\\=\sqrt{(\dfrac{8}{5})^2}\\=|\dfrac{8}{5}|=\dfrac{8}{5}$

Đa thúc `P(x)` có số đơn thức là:

`(101-1):2+1=51`(đơn thức)

Thay `x=-1` vào `P(x)`

`P(-1)=-1+(-1)^3+...+(-1)^101`

`=-1-1-...-1`

`=-1xx51`

`=-51`

Vậy `P(x)=-51<=>x=-1`

`a)275xx23+725xx23`

`=23xx(275+725)`

`=23xx1000`

`=23000`

`b)9/7xx4/5-2/7xx4/5`

`=4/5xx(9/7-2/7)`

`=4/5xx7/7`

`=4/5xx1`

`=4/5`

đua top thg trc còn :=:

còn đua top gr nx :he:

ùi idol hđ =)

lệnh đuỷnh =)

`C=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{48-10\sqrt{7+4\sqrt{3}}}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{48-10\sqrt{4+4\sqrt{3}+3}}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{48-10\sqrt{(2+\sqrt{3})^2}}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{48-10(2+\sqrt{3})}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{48-20-10\sqrt{3}}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5\sqrt{25-10\sqrt{3}+3}}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+5(5-\sqrt{3})}}`

`=\sqrt{4+\sqrt{5\sqrt{3}+25-5\sqrt{3}}}`

`=\sqrt{4+5}`

`=\sqrt{9}`

`=3`