Question

Va rog frumos dacă știți ecuații
Multumesc

Answer 1

a) x+3 = 7

x = 7-3

x = 4

b) 5x-4 = 26

5x = 26+4

5x = 30

x = 30:5

x = 6

c) 7x+3 = 4x+6

7x-4x = 6-3

3x = 3

x = 3:3

x = 1

$d) \frac{3}{4}x+\frac{1}{2} = \frac{4}{3}x+\frac{1}{5}|60$

45x+30 = 80x+12

45x-80x = 12-30

-35x = -18

$x=+\frac{18}{35}$

e) x²+7x-6 = 0

Δ=7²-4*1*(-6) = 73

$x_{1} = \frac{-7+\sqrt{73} }{2}$

$x_{2} =\frac{-7-\sqrt{73} }{2}$

f) 3x²+2x-5 = 0

3x²+5x-3x-5 = 0

x(3x+5) - (3x+5) = 0

(x-1)(3x+5) = 0

x-1 = 0 => x = 1

3x+5 = 0 $=> x = -\frac{5}{3}$

g) 7x²+2x-5 = 3x²+5x-4

7x²-3x²+2x-5x-5+4=0

4x²-3x+1 = 0

4x²+x-4x-1 = 0

x(4x+1) - (4x+1) = 0

(x-1)(4x+1) = 0

x-1 = 0 => x=1

4x+1 = 0 => $x=-\frac{1}{4}$

h) x²-x+1 = 0

Δ = (-1)²-4*1*1 = 1-4 = -3 < 0 => x∉|R

i) 4x²-4x+1 = 0 <=> (2x-1)² = 0

=> $x_{1,2} = \frac{1}{2}$