Задание 735

$$q = 148 - 4p, r(p) = pq\Rightarrow$$

$$r(b) = p(148 - 4p) = 148p - 4p^2$$

$$148p - 4p^2 = 640$$

$$148p-4p^2-640=0$$

$$4p^2-148p+640=0$$

$$p^2-37p+160=0$$

$D=(-37)^2-4\cdot 1\cdot 160=$$1369-640=729$

$p_1=\frac{-(-37)+\sqrt{729} }{2}=$$\dfrac{37+27}2=\dfrac{64}2=32$

$$p_2=\dfrac{37-27}2=\dfrac{10}2=5$$

$$32>5$$