Question

Rezolvati ecuatiile :
a) x²=1
b) 3x² =75
c) x² - 0,25 =0
d) x² = 81
e) 49x² = 121
f ) 2x² - 0,32 = 0
g ) 4x² = 1
h) 25x² = 225
i ) 4x² =0,04
j) 2x² = 8
k)36x² = 144
l) 3x² = 10,8
l)

Answer 1

a)[tex] x^{2} =1 <=> x= \sqrt{1} <=> x= {+1 , -1} [/tex]
$b)3 x^{2} =75 <=> x^{2} =25 <=> x= {+5 , -5}$
c)$x^{2} -0.25=0 <=> x^{2} =0.25 <=> x= \sqrt{0.25} <=> x={+0.5, -0.5}$
d)$x^{2} =81 <=> x={+9, -9}$
e)$49 x^{2} =121 <=> x^{2} = 121/49 <=> x= {-11/7, +11/7}$
f)$2 x^{2} -0,32=0 <=> 2 x^{2} =0,32 <=> x^{2} =0.16 <=> x={+0.4, -0.4}$
g)$4 x^{2} =1 <=> x^{2} =1/4 = 0.25 => X={+0.5, -0.5}$
h)$25 x^{2} =225 <=> x^{2} =9 <=> x={+3, -3}$
i) $4 x^{2} =0.04 <=> x^{2} = 0.01 <=> x= { 0.1 , -0.1}$
j) $2 x^{2} =8 <=> x^{2} =4 <=> x={-2, +2}$
k) $36 x^{2} =144 <=> x^{2} = 4 <=> x= {-2, +2}$
l)$3 x^{2} =10,8 <=> x^{2} =3,6 <=> x= \sqrt{3,6} ={-1,89 ; +1.89}$