Question

Tính giá trị biểu thức:

A = -3/5+[ -2/5+2]

B = 3/7+ [-1/5+ -3/7]

Answer 1

a, \(A=\dfrac{-3}{5}+\left(\dfrac{-2}{5}+2\right)\)

\(A=\dfrac{-3}{5}+\dfrac{3}{5}\)

\(A=0\)

b, \(B=\dfrac{3}{7}+\left(\dfrac{-1}{5}+\dfrac{-3}{7}\right)\)

\(B=\dfrac{3}{7}+\dfrac{-22}{35}\)

\(B=\dfrac{-1}{5}\)

Answer 2

A = -3/5+8/5

=5/5=1

B = 3/7+-22/35

= -7/35= -1/5

Answer 3

A = -3/5+[ -2/5+2]

=-\(\dfrac{3}{5}+1\dfrac{3}{5}\)

=1

B=\(\dfrac{3}{7}+\left[-\dfrac{1}{5}+-\dfrac{3}{7}\right]\)

=\(\dfrac{3}{7}+-\dfrac{22}{35}\)

= -\(\dfrac{1}{5}\)