7.
(m + 5)^2 = m^2 + 10*m + 25
(3 - m)^2 = 9 - 6*m + m^2
(m + 5)^2 - (3 - m)^2 = m^2 + 10*m + 25 - (9 - 6*m + m^2) =
= m^2 + 10*m + 25 - 9 + 6*m - m^2 = 16*m + 16
((m + 5)^2 - (3 - m)^2)/16 = (16*m + 16)/16 = m + 1
8.
Г 6 - 5x > 0
<<br> L -4 - x < 3
Г - 5x > -6 | * (-1)
<<br> L - x < 7 | * (-1)
Г 5x < 6
<<br> L x > - 7
Г x < 1.2
<<br> L x > - 7
- 7 < x < 1.2
Рисунок 4