Question

(x-4)²+(x-2)(x+1)= 5x
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Answer 1

Răspuns:

Salutare!

(x-4)²+(x-2)(x+1)=5x

-desfacem parantezele

(x-4)²=x²-2•4•x+(-4)²=x²-8x+16

(x-2)(x+1)=x²+x-2x-2=x²-x-2

==> x²-8x+16+x²-x-2=5x

2x²-9x+14=5x

2x²-9x-5x+14=0

2x²-14x+14=0 |:2

x²-7x+7=0

∆=b²-4ac=(-7)²-4•1•7=49-28=21

x1= -b -√∆/2a= 7-√21/2

x2= -b +√∆/2a= 7+√21/2