a) (4x+2x+18.5-10).3=66.5
=>4x+2x+18.5-10=22.5
=>6x+90-10=110
=>6x+80=110
=>6x=110-80
=>6x=30
=>x=30:6
=>x=5
b) 15+5.4+3.10+5.3=4.5.x
=>5(3+4+3.2+3)=4.5.x
=>3+4+3.2+3=4x
=>3+4+6+3=4x
=>16=4x
=>x=16:4
=>x=4
My ơi! Công thức thì chịu khó dùng hàm đi. Làm thế nó chép bài đấy!
a) (4x+2x+18.5-10).3=66.5
=>4x+2x+18.5-10=22.5
=>6x+90-10=110
=>6x+80=110
=>6x=110-80
=>6x=30
=>x=30:6
=>x=5
b) 15+5.4+3.10+5.3=4.5.x
=>5(3+4+3.2+3)=4.5.x
=>3+4+3.2+3=4x
=>3+4+6+3=4x
=>16=4x
=>x=16:4
=>x=4