Bài 1:
a: \(=64\cdot12-16\cdot15=528=2^4\cdot3\cdot11\)
b: \(=49\cdot12-120:8=573=3\cdot191\)
c: \(=2500:25+16\cdot30=480+100=580=2^2\cdot5\cdot29\)
d: \(=123-8\cdot9+16\cdot3=99=3^2\cdot11\)
Bài 2:
a: =>7x-15=6
=>7x=21
hay x=3
b: \(\Leftrightarrow x+3=\dfrac{75}{5}=15\)
hay x=12
c: \(125-3\left(x+3\right)=65\)
=>3(x+3)=60
=>x+3=20
hay x=17
d: \(\Leftrightarrow5x=125-75=50\)
hay x=10
Bài 2:
a,(7.x - 15) : 3 = 2
7x = 2 x 3 + 15
7x = 21
x = 21:7
x = 3
b,75:(x+3)=5
x+3=75:5
x+3=15
x=15-3
x=12
c,125-3.(x+3)=65
3 .(x + 3) = 125 - 65
3. (x + 3) = 60
x + 3 = 60 : 3
x+3 = 20
x = 20-3
x=17
d,125−5⋅x=75
5⋅x=125−75
5⋅x=50
x=50:5
x=10
