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9 tháng 4 2017

a) f(x) = x\(^3\) - 2x\(^2\) + x + 1

- g(x) = x\(^3\) + 0x\(^2\) + x + 1

hay f(x) = x\(^3\) - 2x\(^2\) + x + 1

+ [-g(x)] = - x\(^3\) - 0x\(^2\) - x - 1

_________________________

f(x) - g(x) = - 2x\(^2\)

f(x) - g(x) = -2x\(^2\) + 0

+ h(x) = 2x\(^2\) - 1

_________________________

f(x) - g(x) + h(x) = - 1

*Mk nqhĩ là z! bucminh Mk sợ làm hànq dọc cả 3 sẽ hay sai! oaoa

11 tháng 1 2018

f(x) +g(x) + h(x)

=(2x4 - x3 + x - 3 + 5x5) + (-x5 + 5x2 +4x + 2 + 3x5) + (x2 + x + 1 + 2x3 + 3x4)

= 2x4 - x3 + x - 3 + 5x5 +(-x5) + 5x2 +4x + 2 + 3x5 + x2 + x + 1 + 2x3 + 3x4

= 7x5 + 5x4 + x3 +x2 + 6x

f(x) - g(x) - h(x)

=(2x4 - x3 + x - 3 + 5x5) - (-x5 + 5x2 +4x + 2 + 3x5) - (x2 + x + 1 + 2x3 + 3x4)

=2x4 - x3 + x - 3 + 5x5 +x5 - 5x2 -4x - 2 -3x5 - x2 - x - 1 - 2x3 - 3x4

= 3x5 - x4 - 3x3 - 6x2 - 4x - 6

13 tháng 8 2018

Mk làm 1 cách thôi..

f (x) + g (x) - h(x) =\(\left(5x^3-2x^2+x-3\right)+\left(2x^3-5x^2+4\right)-\left(4x^3+5x\right)\)

= \(5x^3-2x^2+x-3+2x^3-5x^2+4-4x^3-5x\)

= \(5x^3+2x^3-4x^3-2x^2-5x^2+x-5x-3+4\)

= \(3x^3-7x^2-4x+1\)

#Yiin - girl ><

13 tháng 8 2018

Cảm ơn ạ

5 tháng 11 2017

Giải như sau.

(1)+(2)⇔x2−2x+1+√x2−2x+5=y2+√y2+4⇔(x2−2x+5)+√x2−2x+5=y2+4+√y2+4⇔√y2+4=√x2−2x+5⇒x=3y(1)+(2)⇔x2−2x+1+x2−2x+5=y2+y2+4⇔(x2−2x+5)+x2−2x+5=y2+4+y2+4⇔y2+4=x2−2x+5⇒x=3y

⇔√y2+4=√x2−2x+5⇔y2+4=x2−2x+5, chỗ này do hàm số f(x)=t2+tf(x)=t2+t đồng biến ∀t≥0∀t≥0
Công việc còn lại là của bạn ! 

29 tháng 3 2019

a. f(x)+g(x)=2x5−4x4+3x3−x2+5x−1+(−x5+2x4−3x3−x2−2x+7)

=2x5-x5-4x4+2x4+3x3-3x3-x2-x2+5x-2x-1+7

=x5-2x4-2x2+3x+6

b. f(x)+h(x)=2x5−4x4+3x3−x2+5x−1+x5−2x4−2x2−x−3

=2x5+x5-4x4-2x4+3x3-x2-2x2+5x-x-1-3

=3x5-6x4+3x3-3x2+6x-4

c. g(x)+h(x)=−x5+2x4−3x3−x2−2x+7+x5−2x4−2x2−x−3

=-x5+x5+2x4-2x4-3x3-x2-2x2-2x-x+7-3

=-3x3-3x2-3x+4

d. f(x)-g(x)=2x5−4x4+3x3−x2+5x−1-(−x5+2x4−3x3−x2−2x+7)

=2x5−4x4+3x3−x2+5x−1-x5-2x4+3x3+x2+2x-7

=2x5-x5-4x4-2x4+3x3+3x3-x2+x2+5x+2x-1-7

=x5-6x4+6x3+7x-8

e. f(x)-h(x)=2x5−4x4+3x3−x2+5x−1-(x5−2x4−2x2−x−3)

=2x5−4x4+3x3−x2+5x−1-x5+2x4+2x2+x+3

=2x5-x5-4x4+2x4+3x3-x2+2x2+5x+x-1+3

=x5-2x4+3x3+x2+6x-4

h. g(x)-h(x)=−x5+2x4−3x3−x2−2x+7-(x5−2x4−2x2−x−3)

=−x5+2x4−3x3−x2−2x+7-x5+2x4+2x2+x+3

=-x5-x5+2x4+2x4-3x3-x2+2x2-2x+x+7+3

=-2x5+4x4-3x3+x2-x+10

f. f(x)+g(x)+h(x)=2x5−4x4+3x3−x2+5x−1+(−x5+2x4−3x3−x2−2x+7)+x5−2x4−2x2−x−3

=2x5-x5+x5-4x4+2x4-2x4+3x3-3x3-x2-x2-2x2+5x-2x-x-1+7-3

=2x5-4x4-4x2+2x+3

g. f(x)+g(x)-h(x)=2x5−4x4+3x3−x2+5x−1+(−x5+2x4−3x3−x2−2x+7)-(x5−2x4−2x2−x−3)

=2x5−4x4+3x3−x2+5x−1+(−x5+2x4−3x3−x2−2x+7)-x5+2x4+2x2+x+3

=2x5-x5-x5-4x4+2x4+2x4+3x3-3x3-x2-x2+2x2+5x-2x+x-1+7+3

=4x+9

n. f(x)-g(x)+h(x)=2x5−4x4+3x3−x2+5x−1-(−x5+2x4−3x3−x2−2x+7)+x5−2x4−2x2−x−3

=2x5−4x4+3x3−x2+5x−1-x5-2x4+3x3+x2+2x-7+x5−2x4−2x2−x−3

=2x5-x5+x5-4x4-2x4-2x4+3x3+3x3-x2+x2-2x2+5x+2x-x-1-7-3

=2x5-8x4+6x3-2x2+6x-11

m. f(x)-g(x)-h(x)=2x5−4x4+3x3−x2+5x−1-(−x5+2x4−3x3−x2−2x+7)-(x5−2x4−2x2−x−3)

=2x5−4x4+3x3−x2+5x−1-x5-2x4+3x3+x2+2x-7-x5+2x4+2x2+x+3

=2x5-x5-x5-4x4-2x4+2x4+3x3+3x3-x2+x2+2x2+5x+2x+x-1-7+3

=-4x4+6x3+2x2+8x-5