Giaỉ phương trình a,√x ²-16 - 3 √x + 4=0 b,√x + 3 + 4 √x-1 = 3
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√x²-16-3√x+4=0
⇔x-16-3√x+4=0
⇔x-12-3√x=0
⇔-3√x=-x+12
⇔-3√x=12-x
⇔9x=144-24x+x²
⇔9x-144+24x+x²=0
⇔33x-144+x²=0
⇔x=$\frac{3(11-√57)}{2}$
√x + 3 + 4 √x-1 = 3
⇔√x+4√x-1=0
⇔8$\sqrt[]{x(x-1)}$ =-x-16(x-1)
⇔64x²-64x=289x²-544x-256
⇔-225x²+480x-256=0
⇔(15x)²-2(15x)(16)+16²=0
⇔(15x-16)²=0
⇔15x-16=0
⇔15x=16
⇔x=$\frac{16}{15}$