f(1) = 4.14 - 31.13 + 4.12 + 15 = 4 - 31 + 4 + 15 = -8

f(-1) = 4.(-1)4 - 31.(-1)3 + 4.(-1)2 + 15 = 4 + 31 + 4 + 15 = 54

P(x)=-31x^3+4x^4+4x^2+15=4x^4-31x^3+4x^2+15

P(1)=4-31+4+15=23-31=-8

P(0)=15

P(-1)=4+31+4+15=56

f(1)= -8

f(-1)= 38

học tốt !!!~~~~~

Trả lời:

= 120

Hok tốt

Đáp án :

4x2+5x4+6x2+80

= 120

Trả lời ;

4x2+5x4+6x2+80= 120

#hoctot

`A(x)+B(x)=(5x^4 -4x^2 +x-2)+(x^4 +3x^2 -4x)`

`=5x^4 -4x^2 +x-2+x^4 +3x^2 -4x`

`=5x^4 +x^4 -4x^2 +3x^2 +x-4x-2`

`=6x^4 -x^2 -3x-2`

a) C1 : 2/5 x 3/7 + 2/7 x 4/7

         = 2/5 x (3/7 + 4/7)

        = 2/5 x 1

        = 2/5

C2 : 2/5 x 3/7 + 2/5 x 4/7

= 6/35 + 8/35

= 2/5 

b) (2/3 - 4/7) x 5/5

= 2/21 x 5/5

= 2/21

C2 : (2/3 - 4/7) x 5/5

= 2/3 x 1 - 4/7 x 1

= 2/3 - 4/7

= 2/21

c) 3/4 x 2/5 - 3/4 x 2/7

= 3/4 x (2/5 - 2/7)

= 3/4 x 4/35

= 3/35

C2 : 3/4 x 2/5 - 3/4 x 2/7

= 3/10 - 3/14

= 3/35

a, 

Cách 1

\(\frac{2}{5}\times\frac{3}{7}+\frac{2}{5}\times\frac{4}{7}\)

\(=\frac{6}{35}+\frac{8}{35}\)

\(=\frac{2}{5}\)

Cách 2 :

\(\frac{2}{5}\times\frac{3}{7}+\frac{2}{5}\times\frac{4}{7}\)

\(=\frac{2}{5}\times\left(\frac{3}{7}+\frac{4}{7}\right)\)

\(=\frac{2}{5}\times1\)

\(=\frac{2}{5}\)

b,

Cách 1 :

\(\left(\frac{2}{3}-\frac{4}{7}\right)\times\frac{5}{5}\)

\(=\frac{2}{21}\times1\)

\(=\frac{2}{21}\)

Cách 2 :

\(\left(\frac{2}{3}-\frac{4}{7}\right)\times\frac{5}{5}\)

\(=\frac{2}{3}\times\frac{5}{5}-\frac{4}{7}\times\frac{5}{5}\)

\(=\frac{2}{3}-\frac{4}{7}\)

\(=\frac{2}{21}\)

c, 

Cách 1 :

\(\frac{3}{4}\times\frac{2}{5}-\frac{3}{4}\times\frac{2}{7}\)

\(=\frac{3}{10}-\frac{3}{14}\)

\(=\frac{3}{35}\)

Cách 2 :

\(\frac{3}{4}\times\frac{2}{5}-\frac{3}{4}\times\frac{2}{7}\)

\(=\frac{3}{4}\times\left(\frac{2}{5}-\frac{2}{7}\right)\)

\(=\frac{3}{4}\times\frac{4}{35}\)

\(=\frac{3}{35}\)

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Đúng 100%

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Cảm ơn bạn nhiều

Thank you very  much

( ^ _ ^ )

Ta có:

f(x) = -15x3 + 5x4 - 4x2 + 8x2 - 9x3 - x4 + 15 - 7x3

      = (5x4 - x4) - (15x3 + 9x3 + 7x3) + (-4x2 + 8x2) + 15

      = 4x4 - 31x3 + 4x2 + 15

4 + 4 x 2 + 4 x 3 + 4 x 4 = ( 4 x 2 + 4 x 3 ) + (4 x 4 + 4) 

                                      =   20 + 20 

                                        = 40 

5 + 5 x 2 + 5 x 3 + 5 x 4 = (5 x 4 + 5 x 2 ) + ( 5 x 3 + 5 )

                                      = 30 + 20 

                                     = 50