УПРОСТИТЕ ВЫРАЖЕНИЕ....

Решите задачу:

$(5c-6)^2 - 25c^2 = 25c^2-60c+36 -25c^2 =-60c+36=12\cdot (3-5c) \\ \\ (7+6p)^2 - 84p = 49 +84p+36p^2 - 84p=36p^2+49 \\ \\ 9t^2 - (8-3t)^2=9t^2 - (64-48t+9t^2)=9t^2 -64+48t-9t^2 = \\ = 48t-64=16 \cdot (3t-4) \\ \\ -40d + (5+4d)^2=-40d + 25 +40d+16d^2 = 16d^2 +25 \\ \\ 36f^2 - (6f-13)^2= 36f^2 - (36f^2 -156f+169)=\\ =36f^2 -36f^2 +156f-169=13\cdot (12f-13) \\ \\ -28y+(2y+7)^2=-28y +4y^2 +28y+49=4y^2+49$