7) 4x²=8x; 8) 7x2=42x; 9) 10x2=80x; 10) 5x2=35x.

Решение уравнений:

7) 4x² = 8x 4x² - 8x = 0 4x(x - 2) = 0 x = 0 или x = 2 8) 7x² = 42x 7x² - 42x = 0 7x(x - 6) = 0 x = 0 или x = 6 9) 10x² = 80x 10x² - 80x = 0 10x(x - 8) = 0 x = 0 или x = 8 10) 5x² = 35x 5x² - 35x = 0 5x(x - 7) = 0 x = 0 или x = 7

Ответ:

• 7) x = 0, x = 2
• 8) x = 0, x = 6
• 9) x = 0, x = 8
• 10) x = 0, x = 7