Tolong donk kawan bsok di kumpul nah, no 6 7 8

Nomor 6
[tex] x^{2} -2x-5=0 \\ \alpha + \beta =2 \\ \alpha \beta =-5 \\ \frac{1}{ \alpha ^{2}} + \frac{1}{ \beta ^{2}} = \frac{ \alpha ^{2} + \beta ^{2}}{ \alpha^{2} \beta ^{2} } \\ = \frac{( \alpha + \beta)^{2}-2 \alpha \beta }{( \alpha \beta)^{2}} \\ = \frac{2^{2}-2(-5)}{(-5)^{2}} \\ = \frac{14}{25} [/tex]

Nomor 7
[tex] x^{2} +2x-3=0 \\ (x+3)(x-1)=0 \\ x_1=-3 \\ x_2=1 \\p= x_1+2=-3+2=-1 \\ q=x_2+2=1+2=3 \\ p+q=-1+3=2 \\ pq=-1.3=-3 \\ [/tex]
PKB-nya
[tex] x^{2} -(p+q)x+pq=0 \\ x^{2} -2x-3=0 \\ [/tex]

Nomor 8
[tex] x^{2} -4x-5 \leq 0 \\ (x-5)(x+1) \leq 0 \\ [/tex]

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            -1                      5

Maka HP = {[tex]x|-1 \leq x \leq 5[/tex]}