cho 1.5 g hỗn hợp gồm fe và ag tác dụng vs 200ml dd h2s04 loãng dư thoát ra 0,336l khí h2

a,tính khối lg fe và ag trong hỗ hợp

b tính thành phần % về khối lg mỗi kim loại

c tính nồng độ mol dung dịch h2s04 loãng đã dùng

x² +2x+4 >0 giải bpt

-2*x^2 -7*x+9 <=0 giải bpt

x^2 -10*x-24 = 0 giải pt

5*x^2 -3*x-2 = 0 giải pt

4 my brother(a)'goes'(b)'to'(c)'climbing'(d)'once' a year

5 (a)'how' do you go (b)'to see' animals at thu le zoo?(c)'once' or twice(d)'a month

1 my aunt(A)'wants'(B)'eat'(C)'some'(D)'sandwiches'

2nam(a)'looks'very(b)'happily'(c)'because'he(d)'smiles' a lot

3 when we (a)'were'(b)'having' dinner (c)'the' lights(d)'were going' out

1 study hard or you'll fail the exam

if you don't

2 i don't see you very often because you live so far 

if you

3 i don't have enough money so i'm not going to buy that skirt

i'd

4 we don't practice english very often we can't communicate with foreingers

we

5 i can't meet you now i have to work

if 

1 tom...(help) his mother do the gardening if she tells him a story this evening

2 if it...(rain) i will stay at home 

3 if they had enoug money they...(buy) a new house

4 they...(pass) the exam if they studied hatder

5 if nick...(have) a bike he could go on a bicycle tour with us

6 if i were you i...(invite) john to the party

7 if the wether....(be) fine the children can walk to school

8 if we meet at 8:30 we...(have) plenty of time 

9 lisaa would find the milk if she...(look) in the fridge

10 if sarah...(ask) her teacher she'd have answered her questions

11 if you spoker louder your classmates...(understand) you

12 david....(arrive) there on time if he left early 

13 you...(have) no trouble at school if you had done your homework

14 if you....(swim) in the lake you'll shiver with cold

15 the door will unlock if he...(press)the yellow button