Вправи: 207

207. Спростіть вираз:

1) (x+5\x+15x-1 + x+5\5x-1x+1) • 1-5xx2+ 5x + x2+ 5x+1 = x2+ x+5x+5+ 5x2- x+25x-55x-1(x+1) • (–5x-1x2+ 5x) + x2+ 5x+1 = 6x2+ 30x5x-1(x+1) • (–5x-1x2+ 5x) + x2+ 5x+1 = 6x(x+5)5x-1(x+1) • (–5x-1x(x+5)) + x2+ 5x+1 = 6xx+5(5x-1)5x-1x+1•x(x+5) + x2+ 5x+1 = –6x+1 + x2+ 5x+1 = -6+ x2+ 5x+1 = x-1(x+1)x+1 = x – 1.

2) (a-3\a-47a-4 – a-3\7a-4a-4) • 7a-49a-3a2 + a2- 144-a = a2- 4a-3a+12-(7a2- 4a-21a+12)7a-4(a-4) • 7a-43a(3-a) + a2- 144-a = a2- 7a+12- 7a2+ 25a-127a-4(a-4) • 7a-43a(3-a) + a2- 144-a = -6a2+ 18a7a-4(a-4) • 7a-4 3a(3-a) + a2- 144-a = -6a(a-3)7a-4(a-4) • 7a-43a(3-a) + a2- 144-a = –6aa-3•(7a-4)7a-4a-4•3a(3-a) + a2- 144-a = 2(a-3)a-4(a-3) + a2- 144-a = 2a-4 – 2- a2+ 14a-4 = 16-a2a-4 = 4-a(4+a)a-4 = –a – 4.