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
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/24 16:48:00
![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](/uploads/image/z/6087828-12-8.jpg?t=%E2%91%A02X%EF%BC%88-3%EF%BC%89%E7%9A%84%E7%AB%8B%E6%96%B9+-4+X%EF%BC%88-3%EF%BC%89%2B15+%E2%91%A1-2%E7%9A%84%E7%AB%8B%E6%96%B9%C3%B74%2F9X%EF%BC%88-2%2F3%EF%BC%89%26sup2%3B%E2%91%A2+-2X%EF%BC%88-3%EF%BC%89%26sup2%3B-4X%28-3%29%2B15+%E2%91%A311%2F5X%EF%BC%881%2F3-%26frac12%3B%EF%BC%89X3%2F11%C3%B75%2F4%E5%8C%96%E7%AE%80%EF%BC%9A-7x%26sup2%3B%2B%EF%BC%886x%26sup2%3B-5xy%EF%BC%89-2%EF%BC%883y%26sup2%3B%2Bxy-x%26sup2%3B%EF%BC%89%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E6%95%B0%E5%80%BC.%26frac12%3Bx-%EF%BC%882x-2%2F3y)
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