Bài 8: Chứng minh rằng
a/ a – (b – c) = (a – b) + c = (a + c) – b
b/ (a – b) + (c – d) = (a + c) – (b + d)
c/ (a – b) – (c – d) = (a + d) – (b +c)
Bài 8: Chứng minh rằng
a/ a – (b – c) = (a – b) + c = (a + c) – b
b/ (a – b) + (c – d) = (a + c) – (b + d)
c/ (a – b) – (c – d) = (a + d) – (b +c)
a)a – (b – c)
ta có:a-(b-c)=a-b+c=a+c-b
b)(a – b) + (c – d)
=a-b+c-d=(a+c)-b-d=(a+c)-(b+d)
c) (a – b) – (c – d)=a-b-c+d=(a+d)-c-b=(a+d)-(b+c)
Đáp án:
Ở dưới `downarrow`
Giải thích các bước giải:
`a, a – (b – c)`
`=a-b+c`
`= (a – b) + c`
`= (a + c) – b`
`b,(a – b) + (c – d)`
`=a-b+c-d`
`= (a + c) – (b + d) `
`c,(a – b) – (c – d)`
`=a-b-c+d`
`= (a + d) – (b +c)`