Question

Tìm x
a)(x+12)^2-9x^2=0
b)20x^3-15x^2+7x=45-38x
c)16x^4-40x^3+10x^2=80x^3-20x^2+196x
d)-4.(x-7)+11x=-x+3.(x+5)
e)4x.(x^2-3)+x=4x^3-3x+5

Answer 1

a: \(\Leftrightarrow\left(x+12-3x\right)\left(x+12+3x\right)=0\)

=>(-2x+12)(4x+12)=0

=>x=-3 hoặc x=6

b: \(\Leftrightarrow20x^3-15x^2+45x-45=0\)

=>\(x\simeq0.93\)

d: =>-4x+28+11x=-x+3x+15

=>7x+28=2x+15

=>5x=-13

=>x=-13/5

e: \(\Leftrightarrow4x^3-12x+x=4x^3-3x+5\)

=>-9x=-3x+5

=>-6x=5

=>x=-5/6