a) x + 15 = 100 -21
\(x+15=79\)
\(x=79-15\)
x = 64
b) \(x.12=100+20\)
\(x.12=120\)
\(x=120:12\)
x = 10
a)x+15=100-21.
=>x+15=79
=>x=79-15.
=>x=64.
Vậy.....
b)x*12=100+12.
=>x*12=120.
=>x=120:12.
=>x=10.
Vây.......
a , X + 15 = 100 - 21
X + 15 = 79
X + 15 = 79
X = 64
a, => x= 100-21-15=64;
Vậy x=64;
b, => x.12=120 hay x= 120: 12=10;
Vậy x=10;
a) \(x+15=100-21\)
\(x+15=79\)
\(x=79-15\)
\(x=64\)
b) \(x.12=100+20\)
\(x.12=120\)
\(x=120\div12\)
\(x=10\)
a ] x + 15 = 100 - 21
x + 15 = 79
x = 79 - 15
x = 64
a,x+15=100-21
x+15=79
x =79-15
x =64
b,x.12=100+20
x.12=120
x =120:12
x =10
a) x + 15 = 100 - 21
x + 15 = 79
x = 79 - 15
x = 64
b) x . 12 = 100 + 20
x . 12 = 120
x = 120 : 12
x = 10
a,x+15=100-21
x+15=79
x=79-15
x=64
Vậy x=64
b,x.12=100+20
x.12=120
x=120:12
x=10
Vậy x=10