共50条信息
若\({{a}^{2}}+5ab-{{b}^{2}}=0\),则\(\dfrac{b}{a}-\dfrac{a}{b}\)的值为 .
运用等式性质的变形,正确的是:
下列等式变形:\(①\)若\(a=b\),则\(\dfrac{a}{x}=\dfrac{b}{x}\);\(②\)若\(ax=bx\),则\(a=b\);\(③\)若\(4a=7b\),则\(\dfrac{a}{b}=\dfrac{7}{4}\);\(④\)若\(\dfrac{a}{b}=\dfrac{7}{4}\),则\(7a=4b.\)其中一定正确的个数是\((\) \()\)
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