Odpowiedź:
zad 1
a) 2x-1=7
2x =8
x=4
b) 6=3-3t
-3 = -3t
t = 1
c) x²+3=28
x²=25
x=5
d) 2n(n-7) =0
2n² - 14n = 0
delta = 196 - 0 = 196
√delty = 14
n1 = 0 poprawne
n2 = 14 nie spełnia warunku
zad 2
a) 5(n+1)-10 = 3n+1
5n+5-10 = 3n+1
2n = 6
n = 3
SPEŁNIA
b) 2(a+1)-3(a-5) = 7a
2a+2-3a+15 = 7a
17 = 8a
17/8 = a
NIE SPEŁNIA
c) 3x(x-5) = (x-2)(3x-3)
3x²-15x = 3x²-3x-6x+6
-6x = 6
x = -1
SPEŁNIA
zad 3
x² + 18 = 9x
x² - 9x + 18 = 0
delta = 81 -72 = 9
√delty = 3
x1 = (9-3)/2 = 3
x2 = (9+3)/2 = 6
3<7
6<7
