3*3*2v2-2*10v2+5*4v2-20=18v2-20v2+20v2-20=18v2-20=2(9v2-10)
(2v6-5v6+24v6) * 2v3 = 21v6 * 2v3= 42v18= 42*3v2= 126v2
1) 7(x + 1) - 2(x - 4) = x - 9
7x + 7 - 2x + 8 = x - 9
5x - x = - 9 - 15
4x = - 24
x = - 6
2) 3(x - 1) - 2(x - 5) = 5x + 13
3x - 3 - 2x + 10 = 5x + 13
x - 5x = 13 - 7
- 4x = 6
x = - 1,5
3) 2 = (3x - 5) - (7 - 4x)
2 = 3x - 5 - 7 + 4x
2 = 7x - 12
7x = 2 + 12
7x = 14
x = 2
Пояснение ко второму : угловой коэффициент равен производной в точке х0