Tính :

a) (a+b+c)^2
b) (a-b-c)^2
c) (a+b-c)^2
d) (a-b+c)^2

a.) a² + b² + c ² + 2ab + 2ac + 2bc

b.) a² + b² + c² - 2ab - 2 ac + 2bc

c ) a² + b² + c² + 2ab - 2ac - 2bc

d.) a² + b² + c² - 2ab + 2ac - 2bc

Step-by-step explanation:

a) ( a + b + c )²

= a² + b² + c² + 2 × ab + 2 × ac + 2 × bc

= a² + b² + c ² + 2ab + 2ac + 2bc

b.) ( a - b - c )

= a² + ( - b )² + ( - c)² + 2a ( -b ) + 2a(-c) + 2(-b)(-c)

= a² + b² + c² - 2ab - 2 ac + 2bc

c.) ( a + b - c )²

= a² + b² + ( -c)² + 2ab + 2a ( - c) + 2 b( -c)

= a² + b² + c² + 2ab - 2ac - 2bc

d.) (a - b + c ) ²

= a² + ( -b)² + c² + 2a(-b) + 2ac + 2c( -b)

= a² + b² + c² - 2ab + 2ac - 2bc

a line is an defined derm because it

a)contains an infinite number of points b) can be used to create other geometric shapes c)describes something that does not have width or depth d) is a term that does not have a formal definition. a line is an undefined term because it: contains an infinite number of points.

the arc length is found by finding the circumference of the full circle (2xpixradius) and then dividing by 4 to find just one quarter of the circle (90 degrees).