Răspuns:
b) x= 1/5
c) x=3
d) x= 5/3
Explicație pas cu pas:
b) 5x^2=1/5 => x^2= 1/5 ÷5= 1/25 => x=√1/25= 1/5
c) 10x^2=x^2+81 => 9x^2=81 => x^2= 81÷9=9 => x=√9=3
d) 9x^2-7=18 => 9x^2= 18+7=25 => x^2= 25/9 => x=√25/9= 5/3
