Question

B1:Tính

a,3.5²-16:2²

b,2².17-2³.14

c,15.141+59.10

d,17.85+15.17-120

e,100-[75-(7-2)]²

g,(2³.9⁴+9³.45):(9^2.10-9²)

B2:Tìm x

a,420+65.4=(x+175):3+30

b,96-3.(x+1)=42

c,(x-47)-115=0

d,(x-36):18=12

e,2^x=16

B3:Tìm x

a,60-3.(x-2)=51

b,4x-20=25:2²

c,8.6+288:(x-3)²=50

mk đang càn rất gấp

Answer 1

Bài 3: 

a: Ta có: 60-3(x-2)=51

\(\Leftrightarrow x-2=3\)

hay x=5

b: Ta có: \(4x-20=25:2^2\)

\(\Leftrightarrow4x=\dfrac{25}{4}+20=\dfrac{105}{4}\)

hay \(x=\dfrac{105}{16}\)

c: Ta có: \(8\cdot6+288:\left(x-3\right)^2=50\)

\(\Leftrightarrow288:\left(x-3\right)^2=50-48=2\)

\(\Leftrightarrow\left(x-3\right)^2=144\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=12\\x-3=-12\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=15\\x=-9\end{matrix}\right.\)