Question

1)1 supra 3 + x supra 2 - 1 = 2
2)7x-5 radical 3 =2 radical 3
3)x la a doua -8x+7=0
4)x la a doua+9x+8=0
5)-x la a doua +5-4=0
6)-x la a doua +x-2=0

Answer 1

Răspuns:

Explicație pas cu pas:

1)1 supra 3 + x supra 2 - 1 = 2

1/3 + x/2 - 1 = 2

x/2 = 2 + 1 - 1/3 = 3 - 1/3 = 9/3 - 1/3 = 8/3

x = 16/3

___________

2)7x-5 radical 3 =2 radical 3

7x - 5√3 = 2√3

7x = 5√3 + 2√3 = 7√3

x = √3

_______________

3)x la a doua -8x+7=0

x^2 - x - 7x + 7 = 0

x(x - 1) - 7(x - 1) = 0

(x - 1)(x - 7) = 0

x - 1 = 0 rezulta x1 = 1

x - 7  = 0 rezulta x2 = 7

_______________

4)x la a doua+9x+8=0

x^2 + x + 8x + 8 = 0

x(x + 1) + 8(x + 1) = 0

(x + 1)(x + 8) = 0

x + 1 = 0 rezulta x1 = -1

x + 8 = 0 rezulta x2 = -8

_____________________

5)-x la a doua +5-4=0

-x^2 = 4 - 5 = -1

x^2 = 1

x1 = 1; x2 = -1

___________________

6)-x la a doua +x-2=0

-x^2 + x - 2 = x^2 - x + 2 = 0

Δ = 1 - 8 = -7 nu are solutii in R

x1 = (1 + √-7)/2

x2 = (-1 - √-7)/2