因式分解(2x-1)3-x3,3是立方,
(2x-1)3-x3
=(2x-1-x)((2x-1)²;+x(2x-1)+x²;)
=(x-1)(4x²;-4x+1+2x²;-x+x²;)
=(x-1)(7x²;-5x+1)
公式
a^3-b^3=(a-b)(a²;+ab+b²;)
因式分解x4-6x²;+25
x4-6x²;+25
=(x^4+10x²;+25)-16x²;
=(x²;+5)²;-(4x)²;
=(x²;-4x+5)(x²;+4x+5)
79乘42加79加79乘57的簡便計算
 ;
79+31/42+79的簡便運算,
孩子這個貌似沒有簡便運算
79*42+79+79*57簡便方法怎麼做
79*42+79+79*57
=79*(42+1+57)
=79*100
=7900
3.21*5.301+5.79*5.301+5.301簡便計算
3.21*5.301+5.79*5.301+5.301
=5.301*(3.21+5.79+1)
=5.301*10
=53.01
求738-301的簡便運算
738-301
=738-(300+1)
=738-300-1
=438-1
=437
301+297簡便運算
301+297
=300+297+1
=597+1
=598
12*301簡便運算.
12X(300+1)=3600+12=3612
1)2分之1x-1=3x(2)2x-3=3x除於2(3)2x-3(2-2x)=15(4)x-7=10-3(x+1)
(5)2分之x+5-3分之2x+1=1(6)0.2分之x+0.5=+0.3分之x+1=2
1)2分之1x-1=3x x-2=6xx=-2/5(2)2x-3=3x除於24x-6=3xx=6(3)2x-3(2-2x)=15 2x-6+6x=158x=21x=21/8(4)x-7=10-3(x+1)x-7=10-3x-34x=14x=7/2(5)2分之x+5-3分之2x+1=13(x+5)-2(2x+1)=63x+15-4x-2=6x=7(6)0.2…