Răspuns:
Explicație pas cu pas:
ex 2
1/(√3 - 1) = (√3 + 1) / (√3 - 1)(√3 + 1) = (√3 + 1) / (3 - 1) = (√3 + 1) / 2
1 / (√7 - √5) = (√7 + √5) / (√7 - √5)(√7 + √5) = (√7 - √5) / (7 - 5) = (√7 - √5)/2
1/2√5 = √5/10
________
-√3/√75 = -√3 / √(3 * 25) = -√3 / 5√3 = -1/5
3√2/2√3 = 3√2*√3 / 2√3*√3 = 3√6/6 = √6/2
5√7/3√5 = 5√7*√5 / 3√5*√5 = 5√35 / 15 = √35/3
__________
-1/√300 = -1 / 10√3 = -√3 /30
3/√250 = 3/5√10 = 3√10/50
2,4/√5 = 24/10√5 = 12/5√5 = 12√5 / 25
_____________________________
Ex 3
(x + 2) / (x^2 - 4) = (x + 2) / (x + 2)(x - 2) = 1 / (x - 2)
(3x - x^2) / (9 - x^2) = x(3 - x) / (3- x)(3 + x) = x / (3 + x)
(4x^2 - 1)/(6x - 3) = (2x + 1)(2x - 1) / 3(2x - 1) = (2x + 1) / 3
(25x^2 - 4) / (15x + 6) = (5x - 2)(5x + 2) / 3(5x + 2) = (5x - 2)/3
________________________
Ex 1
Pui conditia ca numitorii sa nu fie 0
x aprtine lui R-0
___
x apartine lui R - 2
___
x apartine lui R-6
___
x apartine lui R - (-4)
___
x apartine lui R - (-1,2)
