Rút gọn biểu thức
a) 2-{3+5-[-12+5-(-3+7)-12]+32
b)-123-{-123-[-123-(-123)]}
c)32+34+36+38-10-12-14-16-18
Rút gọn biểu thức a) 2-{3+5-[-12+5-(-3+7)-12]+32 b)-123-{-123-[-123-(-123)]} c)32+34+36+38-10-12-14-16-18
By Serenity
By Serenity
Rút gọn biểu thức
a) 2-{3+5-[-12+5-(-3+7)-12]+32
b)-123-{-123-[-123-(-123)]}
c)32+34+36+38-10-12-14-16-18
a) $2-[3+5-(-12+5-(-3+7)-12)+32]$
$=2-[8-(-7+3-7)-12)+32]$
$=2-[8+11-12+32]$
$=2-39=-37$
b) $\text{-123-{-123-[-123-(-123)]}}$
$=\text{-123-{-123-[-123+123]}}$
$=\text{-123+123=0}$
c) $32+34+36+38-10-12-14-16-18$
$=(32-12)+(34-14)+(36-16)+(38-18)-10$
$=20+20+20+20-10=80-10=70$
Đáp án:
Giải thích các bước giải:
a) 2 – { 3 + 5 – [ – 12 + 5 – (- 3 + 7 ) – 12 ] + 32
= 2 – { 3 + 5 – [ -12 + 5 + 3 – 7 – 12 ] + 32
= 2 – { 3 + 5 + 23 ] + 32 = 2 – 3 – 5 – 23 + 32 = 3
b) – 123 – { – 123 – [ – 123 – ( -123 ) ] }
= – 123 – { – 123 – 0 )
= -123 + 123 = 0
c)32+34+36+38-10-12-14-16-18
= ( 32 – 12 ) + ( 34 – 14 ) + ( 36 – 16 ) + ( 38 – 18 ) – 10
= 20 + 20 + 20 + 20 -10 = 80 – 10 = 70