Question

[Nguyễn Thái Sơn]

Bài 1: Tính

a) −415.25−8  b) −154.−1625  c) −54.135 d) 178∶414  e) −209 .513 f) -48 : −245

Bài 2: Tìm x:

a) x + 13 = −73 b) x - 113=−79 c) 2x + 12 = −53 d) −59 : x = 169

Bài 3: Thực hiện phép tính:

a) 65+ (3+ −15) b) −57.211+−57.911+157 c) 819+ 421+25+1721+−2719

help me

Answer 1

[Yen Nhi]

`Answer:`

Bài 1:

a. \(-415.25-8=-10375-8=-10383\)

b. \(\left(-154\right).\left(-1625\right)=250250\)

c. \(-54.135=-7290\)

d. \(178:414=\frac{178}{414}=\frac{89}{207}\)

e. \(-209.513=-107217\)

f. \(-48:-245=\frac{48}{245}\)

Bài 2:

a. \(x+13=-73\Leftrightarrow x=-73-13\Leftrightarrow x=-86\)

b. \(x-113=-79\Leftrightarrow x=-79+113\Leftrightarrow x=34\)

c. \(2x+12=-53\Leftrightarrow2x=-53-12\Leftrightarrow2x=-65\Leftrightarrow x=-32,5\)

d. \(-59:x=169\Leftrightarrow x=-59:169\Leftrightarrow x=-\frac{59}{169}\)

Bài 3:

a. \(65+[3+\left(-15\right)]=65+3-15=\left(65-15\right)+3=53\)

b. \(\left(-57\right).211+\left(-57\right).911+157=\left(-57\right).\left(211+911\right)+157=-63954+157=-63797\)

c. \(819+421+25+1721+\left(-2719\right)=\left(819+1721\right)+\left(421-2719\right)+25=2540-2298+25=267\)