1,tính C= 3^4 + (-3)^5+…….+ (-3) ^201
2 tìm x a, ( x-3) ^206 =/x-3/
b, ( x-2) ( 2x -10) = 0
1,tính C= 3^4 + (-3)^5+…….+ (-3) ^201 2 tìm x a, ( x-3) ^206 =/x-3/ b, ( x-2) ( 2x -10) = 0
By Everleigh
By Everleigh
1,tính C= 3^4 + (-3)^5+…….+ (-3) ^201
2 tìm x a, ( x-3) ^206 =/x-3/
b, ( x-2) ( 2x -10) = 0
Đáp án:
. (−3)201−81−41. (-3)201-81-4
2.a)2.a) [x=3x=4[x=3x=4
b)b)[x=2x=5[x=2x=5
Giải thích các bước giải:
C=34+(−3)5+…+(−3)201C=34+(-3)5+…+(-3)201
C=(−3)4+(−3)5+…+(−3)201C=(-3)4+(-3)5+…+(-3)201
(−3).C=(−3)5+(−3)6+…+(−3)201(-3).C=(-3)5+(-3)6+…+(-3)201
(−3).C−C=[(−3)5+(−3)6+…+(−3)201]−[(−3)4+(−3)5+…+(−3)201](-3).C-C=[(-3)5+(-3)6+…+(-3)201]-[(-3)4+(-3)5+…+(-3)201]
(−4).C=(−3)201−81(-4).C=(-3)201-81
C=(−3)201−81−4C=(-3)201-81-4
2)2)
a)(x−3)206=|x−3|a)(x-3)206=|x-3|
⇒(x−3)206−|x−3|=0⇒(x-3)206-|x-3|=0
⇒(x−3)[(x−3)205−1]=0⇒(x-3)[(x-3)205-1]=0
⇒⇒ [x−3=0(x−3)(205)−1=0[x−3=0(x−3)(205)−1=0
⇒⇒ [x=3(x−3)(205)=1[x=3(x−3)(205)=1
⇒⇒ [x=3x−3=1[x=3x−3=1
⇒⇒ [x=3x=4[x=3x=4
b)(x−2)(2x−10)=0b)(x-2)(2x-10)=0
⇒⇒ [x−2=02x−10=0[x−2=02x−10=0
⇒⇒ [x=2x=5
CHÚC THI TỐT BẠN NHÉ !!!
Đáp án:
`1. ((-3)^(201)-81)/(-4)`
`2. a)` \(\left[ \begin{array}{l}x=3\\x=4\end{array} \right.\)
`b) `\(\left[ \begin{array}{l}x=2\\x=5\end{array} \right.\)
Giải thích các bước giải:
`C=3^4+(-3)^5+…+(-3)^(201)`
`C=(-3)^4+ (-3)^5+…+(-3)^(201)`
`(-3).C=(-3)^5+(-3)^6+…+(-3)^(201)`
`(-3).C-C=[(-3)^5+(-3)^6+…+(-3)^(201)]-[(-3)^4+ (-3)^5+…+(-3)^(201)]`
`(-4).C=(-3)^(201)-81`
`C=((-3)^(201)-81)/(-4)`
`2)`
`a) (x-3)^(206)=|x-3|`
`=> (x-3)^(206)-|x-3|=0`
`=> (x-3)[(x-3)^(205)-1]=0`
`=>` \(\left[ \begin{array}{l}x-3=0\\(x-3)^(205)-1=0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=3\\(x-3)^(205)=1\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=3\\x-3=1\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=3\\x=4\end{array} \right.\)
`b) (x-2)(2x-10)=0`
`=>` \(\left[ \begin{array}{l}x-2=0\\2x-10=0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=2\\x=5\end{array} \right.\)