Question

решите уравнения (2,5-8c)^2-(8c-1,5)*(8c+1,5)=0

Answer 1

(2,5-8c)²-(8c-1,5)×(8c+1,5)=0
2,5²-2×2,5×8c+(8c)²-((8c)²-(1,5)²)=0
6,25-40c+64c²-(64c²-2,25)=0
6,25-40c+64c²-64c²+2,25=0
8,5-40c=0
-40c=-8,5|÷(-40)
c=(-8,5)/(-40)

c=0,2125.

Проверка:

(2,5-8×0,2125)²-(8×0,2125-1,5)×(8×0,2125+1,5)=0
(2,5-1,7)²-(1,7-1,5)×(1,7+1,5)=0
0,8²-0,2×3,2=0
0,64-0,64=0
0=0-истина.