70)
[tex](x + 6) \times (y - 10) = 1 = > [/tex]
Explicație :Pasul 1 :Egalez fiecare termen din paranteza cu 1.
[tex]x + 6 = 1 = > x = 1 - 6 = > x = - 5[/tex]
[tex]y - 10 = 1 = > y = 1 + 10 = 11.[/tex]
VERIFICARE :
[tex]( - 5 + 6) \times (11 - 10) = 1 = > 1(11 - 10) = 1 = > 1 = 1. \: adevarat \: deci \: x = - 5 \: si \: y = 11[/tex]
71)
[tex](x - 9) \times (y + 10) = 1 = > [/tex]
Explicație :Pasul 1 :Egalez fiecare termen din paranteza cu 1.
[tex]x - 9 = 1 = > x = 1 + 9 = > x = 10.[/tex]
[tex]y + 10 = 1 = > y = 1 - 10 = > y = - 9.[/tex]
VERIFICARE :
[tex](10 - 9) \times ( - 9 + 10) = 1 = > 1( - 9 + 10) = 1 = > 1 = 1.adevarat \: x = 10 \: si \: y = - 9.[/tex]
73)
[tex](x - 12) \times (7x + y + 8) = 1 = > [/tex]
[tex]x - 12 = 1 = > x = 1 + 12 = > x = 13[/tex]
[tex]7x + y + 8 = 1 = > 7 \times 13 + y + 8 = 1 = > 91 + y + 8 = 1 = > 99 + y = 1 = > y = 1 - 99 = > y = - 98.[/tex]
VERIFICARE :
[tex](13 - 12) \times (7 \times 13 + ( - 98) + 8) = 1 = > 1(91 - 98 + 8) = 1 = > 1 = 1. \: adevarat \: x = 13 \: si \: y = - 98.[/tex]
[tex]74)(x + 5) \times (8x + y + 11) = 1 = > [/tex]
[tex]x + 5 = 1 = > x = 1 - 5 = > x = - 4.[/tex]
[tex]8x + y + 11 =8 \times ( - 4) + y + 11 = - 32 + y + 11 = 1 = > - 21 + y = 1 = > y = 1 + 21 = > y = 22.[/tex]
VERIFICARE :
[tex]( - 4 + 5) \times (8 \times ( - 4) + 22 + 11) = 1 = > 1( - 32 + 22 + 11) = 1 = > 1 = 1 \: adevarat \: x = - 4 \: si \: y = 22.[/tex]
[tex]75)(x - 12) \times (11x - y + 8) = 1 = > [/tex]
[tex]x - 12 = 1 = > x = 1 + 12 = > x = 13[/tex]
[tex]11x - y + 8 = > 11 \times 13 - y + 8 = 1 = > 143 - y + 8 = 1 = > 151 - y = 1 = > - y = 1 - 151 = > - y = - 150 = > y = 150.[/tex]
VERIFICARE :
[tex](13 - 12) \times (11 \times 13 - 150 + 8) = 1 = > 1(143 - 150 + 8) = 1 = > 1 = 1. \: adevarat \: x = 13 \: si \: y = 150.[/tex]
