计算题 一道解不等式 一道先化简再求值7减x小于等于1减4乘(x减3)(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2
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![计算题 一道解不等式 一道先化简再求值7减x小于等于1减4乘(x减3)(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2](/uploads/image/z/11459319-15-9.jpg?t=%E8%AE%A1%E7%AE%97%E9%A2%98+%E4%B8%80%E9%81%93%E8%A7%A3%E4%B8%8D%E7%AD%89%E5%BC%8F+%E4%B8%80%E9%81%93%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC7%E5%87%8Fx%E5%B0%8F%E4%BA%8E%E7%AD%89%E4%BA%8E1%E5%87%8F4%E4%B9%98%EF%BC%88x%E5%87%8F3%EF%BC%89%EF%BC%88m%2B2%2Fm%26%23178%3B-2m+-1%2Fm-2%EF%BC%89%C3%B72%2Fm%26%23178%3B-4%2C%E5%85%B6%E4%B8%ADm%3D+-1%2F2)
计算题 一道解不等式 一道先化简再求值7减x小于等于1减4乘(x减3)(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2
计算题 一道解不等式 一道先化简再求值
7减x小于等于1减4乘(x减3)
(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2
计算题 一道解不等式 一道先化简再求值7减x小于等于1减4乘(x减3)(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2
7-x≤1-4*(x-3)
7-x≤1-4x+12
3x≤6
x≤2
(m+2/m²-2m -1/m-2)÷2/m²-4,其中m= -1/2
(m+2/m²-2m -1/m-2)÷2/m²-4
=m+2/m²-2m*(m^2-4)/2-1/m-2*(m^2-4)/2
=(m+2)^2/2m-(m+2)/2
=(m+2)【(m+2)/2m-1/2】
=3/2*(-3/2-1/2)
=-3
7-x ≤ 1-4(x-3)
7-x ≤ 1-4x+12
7-x ≤ 13-4x
-x +4x ≤ 13-7
3x ≤ 6
x ≤ 2
[(m+2)/(m²-2m) - 1/(m-2)] ÷ 2/(m²-4)
= [(m+2)/(m²-2m) - m/(m²-2m)] ÷ ...
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7-x ≤ 1-4(x-3)
7-x ≤ 1-4x+12
7-x ≤ 13-4x
-x +4x ≤ 13-7
3x ≤ 6
x ≤ 2
[(m+2)/(m²-2m) - 1/(m-2)] ÷ 2/(m²-4)
= [(m+2)/(m²-2m) - m/(m²-2m)] ÷ 2/(m²-4)
= 2/(m²-2m) × (m²-4)/2
= (m²-4)/(m²-2m)
= (m+2)(m-2) / [m(m-2)]
= (m+2) / m
把 m = -1/2 代入,得
原式
= (2-1/2) /(-1/2)
= - 3
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