Вправи: 792 (1-4)

792. Складіть квадратне рівняння, коренями якого є числа:

x² + bx + c = 0.

1) 2 і 5.

2 + 5 = 7; b = –7;

2 • 5 = 10; c = 10.

x² – 7x + 10 = 0.

2) –6 і 3.

–6 + 3 = –3; b = 3.

–6 • 3 = –18; c = –18.

x² + 3x – 18 = 0.

3) –1 і 7.

–1 + 7 = 6; b = –6.

–1 • 7 = –7; c = –7.

x² – 6x – 7 = 0.

4) –8 і –2.

–8 + (–2) = –10; b = 10.

–8 • (–2) = 16; c = 16.

x² + 10x + 16 = 0.

5) 6 і 13.

6 + 13 = 613; b = –613.

6 • 13 = 2; c = 2.

x² – 613x + 2 = 0; 3x² – 19x + 6 = 0.

6) –3 і 23.

–3 + 23 = –213; b = 213.

–3 • 23 = –2; c = –2.

x² – 213x – 2 = 0; 3x² + 7x – 6 = 0.

7) –34 і 8;

–34 + 8 = 714; b = –714.

–34 • 8 = –6; c = –6.

x² – 714x – 6 = 0; 4x² – 29x – 24 = 0.

8) –7 і –314.

–7 + (–314) = –7314; b = 7314.

–7 • (–314) = 32 = 112; c = 112.

x² + 7314x + 112 = 0;

x² + 10114x + 32 = 0 | • 14;

14x² + 101x + 21 = 0.