TK:

Lời giải:

a.

$=-37-x-23+15=-x-(37+23)+15=-x-60+15=-x-(60-15)=-x-45$

b.

$=176-176+x-42=0+x-42=x-42$

c.

$=1270-1270+2x+31=0+2x+31=2x+31$

d.

$=2x-141-231+461=2x-(141+231)+461=2x-372+461$

$=2x+(461-372)=2x+89$

các pro giúp em vớiiiiiiiiii ;-;

B) 2x + (-416) - (231 - 416 )

= 2x - 416 - 231 + 416

= 2x - ( 416 +231 - 416 )

= 2x - 231

D) 211-(123-x)+(123-211)

= 211 - 123 + x + 123 - 211

= ( 211 - 123 +123 - 211 )+ x

= 0+ x

= x

b) 2x + (-461) - (231 - 416)

= 2x - 461 - (231 - 416)

= 2x - 461 + 185

= 2x - 276

d) 211 - (123 - x) + (123 - 211)

= 211 - 123 + x + 123 - 211

= (211 - 211) + (-123 + 123) + x

= 0 + 0 + x

= x

(461-148)-(461-80)=461-148-461+80=(461-461)-(148-80)=-68

Điều kiện: x ≠ 0; x ≠ 1 và x ≠ 3

\(262+\left(2x-123\right)=283\\ \Rightarrow2x-123=21\\ \Rightarrow2x=144\\ \Rightarrow x=72\)

\(213-\left(x+84\right)=-16\\ \Rightarrow-\left(x+84\right)=-229\\ \Rightarrow x+84=229\\ \Rightarrow x=145\)

\(416+\left(x-45\right)=387\\ \Rightarrow x-45=-29\\ \Rightarrow x=16\)

help

262+(2x-123)=283

2x=  -139 +283

 2x= 144

x=72

[461+(-76)+40]+ ( -461)

=(385+40)+ ( -461)

=425+ ( -461)

=-36