Question

tìm số nguyên x :

a) 9- 25 = ( 7- x) - (25+7)

b) -6x=18

c)35- 3. /x/ = 5.(2³- 4)

d)10+2./x/=2.(3²-1)

Answer 1

b. -6x=18

=> x = 18 : (-6)

=> x = -3

c. 35-3.|x|=5.(2³-4)

=> 35-3.|x|=5.(8-4)

=> 35-3.|x|=5.4

=> 35-3.|x|=20

=> 3.|x|=35-20

=> 3.|x|=15

=> |x|=5

=> x \(\in\){-5; 5}

d. => 10+2.|x|=2.(9-1)

=> 10+2.|x|=2.8

=> 10+2.|x|=16

=> 2.|x|=16-10

=> 2.|x|=6

=> |x|=3

=> x \(\in\){-3; 3}

Answer 2

a. 9 - 25 = ( 7 - x ) - ( 25 + 7 )

=> -16 = 7 - x - 32

=> x = 7 - 32 + 16

=> x = -9.

Answer 3

9-25=(7-x)-(25+7)
9-25=7-x-25-7
=> 9-25-7+25+7=-x
=> x=-9