①2X(-3)的立方 -4 X(-3)+15 ②-2的立方÷4/9X(-2/3)²③ -2X(-3)²-4X(-3)+15 ④11/5X(1/3-½)X3/11÷5/4化简:-7x²+(6x²-5xy)-2(3y²+xy-x²)先化简,再求数值.½x-(2x-2/3y
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①2X(-3)的立方 -4 X(-3)+15 ②-2的立方÷4/9X(-2/3)²③ -2X(-3)²-4X(-3)+15 ④11/5X(1/3-½)X3/11÷5/4化简:-7x²+(6x²-5xy)-2(3y²+xy-x²)先化简,再求数值.½x-(2x-2/3y
①2X(-3)的立方 -4 X(-3)+15 ②-2的立方÷4/9X(-2/3)²
③ -2X(-3)²-4X(-3)+15 ④11/5X(1/3-½)X3/11÷5/4
化简:
-7x²+(6x²-5xy)-2(3y²+xy-x²)
先化简,再求数值.
½x-(2x-2/3y²)+(-3/2x+1/3y²)其中x= -1/4 ,y= -½
①2X(-3)的立方 -4 X(-3)+15 ②-2的立方÷4/9X(-2/3)²③ -2X(-3)²-4X(-3)+15 ④11/5X(1/3-½)X3/11÷5/4化简:-7x²+(6x²-5xy)-2(3y²+xy-x²)先化简,再求数值.½x-(2x-2/3y
①2X(-3)的立方 -4 X(-3)+15
=2x (-27) +12+15
=-54+12+15=-27
②-2的立方÷4/9X(-2/3)²
=-8x 9/4 x 4/9 =-8
③ -2X(-3)²-4X(-3)+15
=12 x 9 +12+15
=135
④11/5X(1/3-½)X3/11÷5/4
=11/5X(-1/6) X3/11÷5/4
=3/5 X(-1/6)x4/5
=12/25 X(-1/6)
=-2/25
化简:
-7x²+(6x²-5xy)-2(3y²+xy-x²)
=-7x²+6x²-5xy-6y²-2xy+2x²
=-5x²-7xy
先化简,再求数值.
½x-(2x-2/3y²)+(-3/2x+1/3y²)其中x= -1/4 ,y= -½
=½x-2x+2/3y²-3/2x+1/3y²
=y²-3x
当x= -1/4 ,y= -½ ,y²-3x=1/4+3/4=1