Найдите область определения функции(срочно надо) 7.24 а и б

$a) \left \{ {{x-12 \geq 0} \atop {x^2-1 \neq 0}} \right. \ \ \left \{ {{x \geq 12} \atop {x^2\neq 1}} \right. \ \ \left \{ {{x \geq 12} \atop {x\neq б1}} \right.$
Ответ: [12;+бесконечность)

0} \right. \ \ \left \{ {{x^2+7x-8 \leq 0} \atop {x+9>0} \right. \ \ \left \{ {{x^2-x+8x-8 \leq 0} \atop {x>-9} \right. \ \ \left \{ {{x(x-1)+8(x-1) \leq 0} \atop {x>-9} \right.\\ \\ \ \ \left \{ {{(x-1)(x+8) \leq 0} \atop {x>-9} \right. \ \ \left \{ {{x=[-8;1]} \atop {x>-9} \right." alt="b) \left \{ {{-x^2-7x+8 \geq 0} \atop {x+9>0} \right. \ \ \left \{ {{x^2+7x-8 \leq 0} \atop {x+9>0} \right. \ \ \left \{ {{x^2-x+8x-8 \leq 0} \atop {x>-9} \right. \ \ \left \{ {{x(x-1)+8(x-1) \leq 0} \atop {x>-9} \right.\\ \\ \ \ \left \{ {{(x-1)(x+8) \leq 0} \atop {x>-9} \right. \ \ \left \{ {{x=[-8;1]} \atop {x>-9} \right." align="absmiddle" class="latex-formula">
Ответ: [-8; 1]