Question

tim x,biet

a, 1-[15+11­] = x-[25-9]

b,2-x=17-[-5]

c, x-12=[-9­]-15

d,9-25=[ 7- x­] -[25+7]

Answer 1

a, 1-[15+11­] = x-[25-9]

1-16=x-16

-15=-x-16

x=-15+16

x=1

b,2-x=17-[-5]

2-x=17+5

2-x=22

x=2-22

x=-20

c, x-12=[-9­]-15

x-12=-24

x=-24+12

x=-12

d,9-25=[ 7- x­] -[25+7]

-16=[7-x]-32

[7-x]-32=-16

7-x=-16+32

7-x=16

x=7-16

x=-9