Question

Rezolvati in R ecuatia:
a)2x³-x+3=5(x+2/5x³-2)-4x
b)3x(x²-x+1)-4x=5x²+2(1-x²)+3x³-x
c)(4x-1)(4x+1)-5x=-4(x-4x²)-7(x+3)

Answer 1

a)2x³-x+3=5(x+2x³/5-2)-4x
2x³-x+3=5x+2x³-10-4x
-x+3=x-10
2x=13
x=13/2
x=6,5


b)3x(x²-x+1)-4x=5x²+2(1-x²)+3x³-x
3x³-3x²+3x-4x=5x²+2-2x²+3x³-x
-3x²=3x²+2
-3x²=3x²+2
6x²=-2
x²=-2/6=-1/3              i²=-1    i=√-1    ⇒ x=i/√3                     

c)(4x-1)(4x+1)-5x=-4(x-4x²)-7(x+3)
16x²-1-5x=-4x+16x²-7x-21
-1-5x=-11x-21
6x=-20
x=-20/6=-10/3=-3  1/3