721° Вправа 721Алгебра 8 клас Тарасенкова 2025 · § 17 · стор. 214

721. Запишіть квадратне рівняння за його коефіцієнтами:

1) ${\displaystyle a=}$${\displaystyle 3}$, ${\displaystyle b=}$${\displaystyle 2}$, ${\displaystyle c=}$${\displaystyle 4}$ ⇒ ${\displaystyle 3x^2+2x+4=}$${\displaystyle 0}$;

2) ${\displaystyle a=}$${\displaystyle 1}$, ${\displaystyle b=}$${\displaystyle -3}$, ${\displaystyle c=}$${\displaystyle 2}$ ⇒ ${\displaystyle x^2-3x+2=}$${\displaystyle 0}$;

3) ${\displaystyle a=}$${\displaystyle 2}$, ${\displaystyle b=}$${\displaystyle 0}$, ${\displaystyle c=}$${\displaystyle -8}$ ⇒ ${\displaystyle 2x^2-8=}$${\displaystyle 0}$;

4) ${\displaystyle a=}$${\displaystyle -1}$, ${\displaystyle b=}$${\displaystyle -2}$, ${\displaystyle c=}$${\displaystyle 5}$ ⇒ ${\displaystyle -x^2-2x+5=}$${\displaystyle 0}$;

5) ${\displaystyle a=}$${\displaystyle 1}$, ${\displaystyle b=}$${\displaystyle -7}$, ${\displaystyle c=}$${\displaystyle 0}$ ⇒ ${\displaystyle x^2-7x=}$${\displaystyle 0}$;

6) ${\displaystyle a=}$${\displaystyle 4}$, ${\displaystyle b=}$${\displaystyle 8}$, ${\displaystyle c=}$${\displaystyle 0}$ ⇒ ${\displaystyle 4x^2+8x=}$${\displaystyle 0}$.

Зведені рівняння (у них ${\displaystyle a=}$${\displaystyle 1}$): 2) ${\displaystyle x^2-3x+2=}$${\displaystyle 0}$ і 5) ${\displaystyle x^2-7x=}$${\displaystyle 0}$.