a)x=1\2+3\4

x=5\4

b)-5\6-x=3\12

x=-5\6-3\12

x=-13\12

a)chu vi cua khu dat la

3\4+5\8=11\8(km)

nua chu vi cua khu dat la

11\8/2=11\16(km)

b)chieu dai hon chieu rong la

3\4-5\8=1\8

thoi gian buoi toi tu 19h den 21h30ph la

21h30ph-19ph=2h30ph=5\2h

45ph=3\4h

thoi gian binh rua bat, quet nha va lam bai tap la

1\4+1\6+1=17\12h

so thoi gian con lai la

5\2-17\12=13\12h

vi 9\12<13\12=>binh co du thoi gian de xem het phim

a)=>x*21=7*6

=>x*21=42

=>x=42/21

x=2

b)=>y*20=(-5)*28

=>y*20=-140

=>y=-140/20

y=-7

vi tia AM va AN doi nhau

=>MAP va PAN la goc ke bu

=>MAP+PAN=180'.Ma PAM=33' nen ta co 33'+PAN=180'

=>PAN=180'-33'=147'

vi tia AQ nam giua 2 tia APva AN

=>PAQ+QAN=147'

=>PAN=147'-QAN=147'-58'=89'

=(x²)+2.x².1/2+(1/2)²

=(x²+1/2)²

-hinh tron la hinh gom cac diem nam tren duong tron va cac diem nam ben trong duong tron do

-duong tron tam o ban kinh r la hinh gom cac diem cach o 1 khoang bang r ki hieu(o;r)

3\6=2\4;2\3=4\6;4\6=2\3;4\2=6\3

tỉ số % muối trong nước biển la

3*100\6%=1*100\2%=50%

thoi gian ban an di :

8h25ph-7h40ph=45phut=3\4gio

thoi gian ban binh di:

8h25ph-7h55ph=30ph=1\2gio

quang duong ban an di la

12*3\4=9(km)

quang duong ban binh di la

14*1\2=7(km)

quang duong AB dai la

9+7=16(km)