Question

a, (x - 15) . 4 = 0
b, 31 (x - 7) = 31

c, (x - 15) - 75 = 0

d, 575 - (6x + 70) = 445

Answer 1

a: =>x-15=0

hay x=15

b: =>x-7=1

=>x=8

c: =>x-15=75

hay x=90

d: =>6x+70=130

=>6x=60

hay x=10

Answer 2

\( (x - 15) . 4 = 0\)

\( x - 15= 0:4\)

\(x - 15=0\)

\(x\)\(=0+15\)

\(x=15\)

\(------------------\)

\( 31 (x - 7) = 31\)

\(x-7=31:31\)

\(x-7=1\)

\(x=1+7\)

\(x=8\)

\(-------------------\)

\( (x - 15) - 75 = 0\)

\(x-15=0+75\)

\(x-15=75\)

\(x=75+15\)

\(x=90\)

\(-------------------\)

\( 575 - (6x + 70) = 445\)

\(6x + 70 = 575 - 445\)

\(6x + 70 =130\)

\(6x=130-70\)

\(6x=60\)

\(x=60:6\)

\(x=10\)