a, 98+8x= 6x+46
⇔ 8x-6x= -98+46
⇔2x= -50
⇔x=-25
b, 3600:[(5x+335):x]=50
⇔3600:($\frac{5x+335}{x}$ ) =50
⇔3600*($\frac{x}{5x+335}$ )=50
⇔ 720*$\frac{x}{x+67}$ =50 ( chia vế trái cho 5)
⇔$\frac{720x}{x+67}$ =50
⇔720x=50(x+67)
⇔720x=50x+3350
⇔720x-50x=3350
⇔670x=3350
⇔x=5
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