Question

rút gọn các biểu thức

x + 45 - [90+(-20)+5-(-45)]

x+(294+13)+(94-13)

Answer 1

x+45-[90+(-20)+5-(-45)]

=x+45-90-(-20)-5+(-45)

=x+(45+-45)-90+20-5

=x+0-(90-20+5)

=x-75

x+(294+13)+(94-13)

=x+294+13+94-13

=x+294+94+(13-13)

=x+388+0

=x+388

Answer 2

x + 45 - [90 + (-20) + 5 - (-45)]

x + 45 - [90 + (-20) + 5 + 45]

x + 45 - 120

x + (-75)

x + (294 + 13) + (94 - 13)

x + 307 + 81

x + 388

Answer 3

\(x+45-\left[90+\left(-20\right)+5-\left(-45\right)\right]\\ =x+45-\left(90-20+5+45\right)\\ =x+45-120\\ =x-75\)

\(x+\left(294+13\right)+\left(94-13\right)\\ =x+307+81\\ =x+388\)