<span>5x + 6 + (x - 3) = (5 + x) - 4
5x + 6 + x - 3 = 5 + x - 4
6x + 3 = 1 + x
6x - x = 1 - 3
5x = -2
x = -2 : 5
x = -0.4
Ответ: -0,4</span>
1,3*(5-6)-1.7*(4-5)=1,3*(-1)-1,7*(4-5)=-1,3-1,7=-3
Решил методом разложения на множители.
(x-5)(2x+4)=0
x-5=0
2x+4=0
x1=5
x2=-2
Arctg(1)- arctg(-1) = π/4 -(-π/4)=π/4 + π/4 =2π/4 = π/2