Violympic toán 8

Miamoto Shizuka

Evaluate the expression at

Fill in the blank: ............

Fill in the blank:  Fill in the blank:  
Evaluate , given and .
Answer:
Given .
Evaluate A at .
Answer: A
Given .
Evaluate A at .
Answer: A
Given a rectangle with dimension by . Find the area of the rectangle when and .
Answer: Given and . Evaluate .Answer:
Given and . Evaluate .
Answer:
Phương An
19 tháng 11 2016 lúc 15:05

Evaluate the expression at

x3 + 12x + 48x + 64

= (x + 4)2

= (- 4 + 4)2

= 02

= 0

Fill in the blank: ............

x3 - a = (x - 2)(x2 + 2x + 4)

x3 - a = x3 - 8

a = 8

Fill in the blank: (x - 1)3 = x3 - 3x2 + 3x - 1 Fill in the blank: (x + 1)3 = x3 + 3x2 + 3x + 1
Evaluate , given and .
Answer:

a + b = 8

(a + b)2 = 82

a2 + b2 + 2ab = 64

a2 + b2 + 2 . 10 = 64

a2 + b2 + 20 = 64

a2 + b2 = 64 - 20

a2 + b2 = 44

(a - b)2

= a2 - 2ab + b2

= 44 - 2 . 10

= 44 - 20

= 24
Given .
Evaluate A at .
Answer: A

A = (x - 5)(x2 + 5x + 25) - x2(x + 3) + 3x2

= x3 - 125 - x3 - 3x2 + 3x2

= - 125

Given .
Evaluate A at .
Answer: A

A = (x - 5)(2x + 1) - 2x(x - 3) + 3x= 2x2 + x - 10x - 5 - 2x2 + 6x + 3x= - 5Given a rectangle with dimension by . Find the area of the rectangle when and .
Answer: Given and . Evaluate .Answer: a - b = 5(a - b)2 = 52a2 - 2ab + b2 = 25a2 + b2 - 2 . 4 = 25a2 + b2 - 8 = 25a2 + b2 = 25 + 8a2 + b2 = 33a3 - b3 = (a - b)(a2 + ab + b2) = 5 . (33 + 4)= 5 . 37= 185
Given and . Evaluate .
Answer: a + b = 5(a + b)2 = 52a2 + 2ab + b2 = 25a2 + b2 + 2 . 4 = 25a2 + b2 + 8 = 25a2 + b2 = 25 - 8a2 + b2 = 17a3 + b3= (a + b)(a2 - ab + b2)= 5 . (17 - 4)= 5 . 13= 65

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