Question

C = -a+(b-d)-(c+a)-(b-a) với a =3/4;b=-5/8;c=7/5;d=-9/10

Answer 1

\(C=-a+\left(b-d\right)-\left(c+a\right)-\left(b-a\right)\)
\(C=-a+b-d-c-a-b+a\)
\(C=\left(-a+a-a\right)+\left(b-b\right)-c-d\)
\(C=-a+0-c-d\)
Thay \(a=\dfrac{3}{4};c=\dfrac{7}{5};d=\dfrac{-9}{10}\) vào biểu thức C, ta có:

\(C=-\dfrac{3}{4}-\dfrac{7}{5}-\dfrac{-9}{10}\)

\(C=-\dfrac{5}{4}\)

Answer 2

Với \(a=\dfrac{3}{4};b=-\dfrac{5}{8};c=\dfrac{7}{5};d=-\dfrac{9}{10}\)

\(C=-a+\left(b-d\right)-\left(c+a\right)-\left(b-a\right)\\ =-a+b-d-c-a-b+a\\ =-a-d-c\\ =-\dfrac{3}{4}-\dfrac{7}{5}+\dfrac{9}{10}\\ =-\dfrac{5}{4}\)