42/212 Rozwiąż
a)
(2x-1)(2x+1)-(4x+5)^2=-4x-2
b)
(x+3)^2-2(x-2)^=4x+10
c)
x^2+5/3-(x+2)^2/4=x-1
d)
x(x-1)/2+x(x-3)/3+(4-x)(4+x)=10
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a) (2x-1)(2x+1)-(4x+5)²=-4x-2
4x²+2x-2x-1-16x²-40x-25+4x+2=0
-12x²-36x-24=0
Δ=b²-4ac
Δ=(-36)²-4·(-12)·(-24)
Δ=1296-1152
Δ= 144
√Δ=12
x₁=-b+√Δ / 2a
x₁=36+12 / 2·(-12)
x₁=48 / -24
x₁=-2
x₂= -b-√Δ / 2a
x₂=36-12 / -24
x₂=24 / -24
x₂=-1
b)(x+3)²-2(x-2)²=4x+10
x²+6x+9-2(x²-4x+4)-4x-10=0
x²+6x+9-2x²+8x-8-4x-10=0
-x²+10x-9=0
Δ=b²-4ac
Δ=10²-4·(-1)·(-9)
Δ=100-36
Δ= 64
√Δ=8
x₁=-b+√Δ / 2a
x₁=-10+8 / 2·(-1)
x₁= -2 / -2
x₁=1
x₂= -b-√Δ / 2a
x₂=-10-8 / -2
x₂=-18 / -2
x₂=9
c) x²+5/3-(x+2)²/4=x-1
x²+5/3-(x²+4x+4)/4-x+1=0 /·12
12x²+20-3x²-12x-12-12x+12=0
9x²-24x+20=0
Δ=b²-4ac
Δ=(-24)²-4·9·20
Δ=576-720
Δ= -144
brak rozwiązań
d) x(x-1)/2+x(x-3)/3+(4-x)(4+x)=10
x²-x/2+x²-3x/3+16+4x-4x-x²-10=0 /·6
3x²-3x+2x²-6x+96-6x²-60=0
-x²-9x+36=0
Δ=b²-4ac
Δ=(-9)²-4·(-1)·36
Δ=81+144
Δ= 225
√Δ=15
x₁=-b+√Δ / 2a
x₁=-9+15 / 2·(-1)
x₁= 6 / -2
x₁=-3
x₂= -b-√Δ / 2a
x₂=-9-15 / -2
x₂=-24 / -2
x₂=12
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