Question

Answer 1

3:

a: (x-4)+5=9

=>x-4=4

=>x=8

b: \(x⋮10\)

=>\(x\in B\left(10\right)\)

mà x<40

nên \(x\in\left\{10;20;30\right\}\)

c: 4x-5=9

=>4x=14

=>x=14/4=7/2

2:

a: (x-2)-3=7

=>x-2=10

=>x=12

b: \(x⋮7\)

=>\(x\in B\left(7\right)\)

mà x<18

nên \(x\in\left\{7;14\right\}\)

c: 3x-7=5

=>3x=12

=>x=4