Завдання 1301 - 1402 » 1381

Знайди корінь рівняння: 1) 3(x – 4) = 5x; 3x – 12 = 5x; 3x – 5x = 12; –2x = 12; x = 12 : (–2); x = –6. 2) –(5x – 8) = –x; –5 + 8 = –x; –5x + x = –8; –4x = –8; x = –8 : (–4); x = 2. 3) –5(x + 2) = –15; –5x – 10 = –15; –5x = –15 + 10; –5x = –5; x = 1. 4) 7(x – 2) = 6(x +1); 7x – 14 = 6x + 6; 7x – 6x = 6 + 14; x = 20. 5) 3(–x + 2) = –(x – 8); –3x + 6 = –x + 8; –3x + x = 8 – 6; –2x = 2; x = 2 : (–2); x = –1. 6) –5(7 – x) = 6(x + 2); –35 + 5x = 6x + 12; 5x – 6x = 12 + 35; –x = 47; x = 47 : (–1); x = –47.