ÔN TẬP HÈ CHO HS - LỚP 8

A. Lí THUYT Cõu 1 !"ạ Cõu 2: #$%&%'()*+,-$.%ập minh hoạ hai quy tắc biến đổi đó? Cõu 3: #$%&%'()*+,-$.%ập minh hoạ các quy tắc biến đổi đó? Cõu 4 / -01--234--567+$8$& / & #&9& #&97%:*7-2456%;#<=>---0? Cõu 5 Thế nào là hại tam giác đồng dạng? Nêu các trờng hợp đồng dạng của hai tam giác, hai tam giác vuông. Cõu 6 / 5$-@- -&-AB /C!"# -&DEFG!. Hình lập phơng đó chứa đợc bao nhiêu lít nớc? Cõu 7 /()- H -I H ) J I H -I K - H /L H ! M I H ) J I H -I K - H H H -) K N) H - M H H -) K FO- K -FP- B : T LUN DNG I: Gii cỏc phng trỡnh sau Bi 1 /OBQFEFG<GB RSBTOEOBQG -/UVB<O/EGVSBQF/ !R2x + 5 = 20 3x WR<XBQYEP ZRBTSEFY<GB RBVOBTF/EP RSBTFEBQS R U FF[ O XG + = xx \ROVBQF/EGB<U 8/OBQ[EP &/ x xxx = + S OS X O [ FO /OB<SEP /XBQOPEP RFQ [ GO x E X S x /FG<UBE]<SB */ O F S x QBE X O x + / F O O S x x+ = Bi 2 /+V+ O <F/E+ O <G+Q[EP /+V+< O F /VO+QG/EP -/X+ O QFEX+ !/+ O TO+EYP g) (2y 1) 2 (y + 3) 2 = 0 /O+ O FF+EP / VO+<S/V+QF/Q+V+<O/ESV+QO/ O \/V+ O <O+QF/T]EP Bài 3 a) S Fx = / S O Sx x = -/ FS = xx !/ F X S F GV O/ O x x x + = W/ PGG = x Z/ O Sx = g) G + x ESB<O/ S O S O Gx x x + = / FS = xx Bi 4 / O O O S = + + x x x x RVBTO/V S O BT[/EP -R O O O S = + + x x x x !/ F SO F SO F O + = + x x x x x x ZR O FB OB B FB = + + / F O F x x x x + = / x x x x O F S + + + EO i/ G F S F O = + xx \/ ( )( ) FOFO X F FOFO O + += + + xxx x x x 8/ F S GO F FS = + x x x x &/ /O/VFV FFS O F F O + = + xx x xx / F / /OV OF O O − =− − + xxxx x / + + − O O x x X FF O S O O − − = − x x x / O O B X B OB B F B F B F + + = + − −  p) S GO SO X F O O + − = −+ + − x x xx x x q) O OOO ] SU SS x xx x x x xx − − = − − + − DẠNG II: Giải bất phương trình và biểu diễn tập hợp nghiệm trên trục số Bài 1: ;7^%!_?:)"-^` / O US [ UO − ≥ − xx /SBTVUBQO/aGBQX -/ O F G x + < O O S x −  bF !/ X OS FP S G OO − <+ + xx  W/OBQG ≤ U Z/OBTScP / OP [ G <− x / O FS S FO + > − xx /TXQOBbP \/ SV F/ O F X S x x− + + ≤ 8/OBQSVBTO/bGBTVOBTX/ &/ ( ) S B F B O F FP G > + − + /OVOB<S/VBQX/bVB<O/ O QF / F F O > − x /BVB<O/TVBQF/VBQO/bFO /GB<VFPB<S/a]<OB */SBQXaOBQS /SB< x xx −+ − ≤ + G O /OVS S O ^/XB<Y ≥ SVSB<F/<OBQF / X OS FP S G OO − <+ + xx /SBTVUBQO/aGBQX / G OS S O xx − < − Bài 2 /#B^-@-O<GBd@-SVO<B/ /LE YB GB − − #-2BL! -/#B1@- xOG O − 81 !/@eOB O QXBQSaPDfB DẠNG III: Giải bài toán bằng cách lập phương trình Bài 1g:-2^`eGPh`%+&i^`8#^`4' Bài 2j M -B! K  K ) H L) H ) H N1 H X K  K  M -! K  K ) H N) H ) H L1 H G# 87 --k$$`-!lD-&%O8R Bài 3=0-k-4-YOm!%-m3FF# !: -80 Bài 4 j30BW+nL$ND`-SP8Ro$N04&%:-30p*+mL D`-OX8RN$0.-3$G0SPq# *r0LN Bài 5 j30BWAnL9ND`-FO8R=mnN$L(04D `-&%FP8R)0mm0&%FGq# 3!%*70LN' Bài 6 >q-U0j3-B!lnL$N--S[8p+&@-*+m)L&q-FF0SPq # 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