Question

Ajutati-ma urgent dau coroana!!!

Answer 1

a) x+8=2
x=2-8
x=-6

b) 2x-3=-7
2x-3+7=0
2x+4=0
2x=-4
x=-2

c) x²-5x+6=0
a=1; b=-5; c=6
Δ=b²-4ac
Δ=(-5)²-4×1×6
Δ=25-24
Δ=1⇒√Δ=√1⇒Δ=1
x1=-b+√Δ/2a⇒5+1/2⇒6/2⇒x1=3
x2=-b-√Δ/2a⇒5-1/2⇒4/2⇒x2=2

d)x²+4x+3=0
a=1; b=4; c=3
Δ=b²-4ac
Δ=4²-4×1×3
Δ=16-12
Δ=4⇒√Δ=√4⇒Δ=2
x1=-b+√Δ/2a⇒-4+2/2⇒-2/2⇒x1=-1
x2=-b-√Δ/2a⇒-4-2/2⇒-6/2⇒x2=-3

e) x-3/2 +7x-1/5=0
Amplificam fractia x-3/2 cu 5 si fractia 7x-1/5 cu 2 pentru a scapa de numitor.
5(x-3)+2(7x-1)=0
5x-15+14x-2=0
19x-17=0
a=0; b=19;c=17
Δ=b²-4ac
Δ=19²-4×0×17
Δ=361⇒√Δ=√361⇒Δ=19
x1=-b+√Δ/2a⇒-19+19/0⇒x1=0
x2=-b-√Δ/2a⇒-19-19/0⇒x2=0

f) (x-3)(x+9)=0
x²+9x-3x-27=0
x²+6x-27=0
a=1; b=6; c=-27
Δ=b²-4ac
Δ=6²-4×1×(-27)
Δ=36+108
Δ=144⇒√Δ=√144⇒Δ=12
x1=-b+√Δ/2a⇒-6+12/2⇒6/2⇒x1=3
x2=-b-√Δ/2a⇒-6-12/2⇒-18/2⇒x2=-9