Question

simplify the following:(a-2b+5c)(a-b)-(a-b-c)(2a+3c)+(6a+b)(2c-3a-5b)

Answer 1

$- 19a {}^{2} - 34ab - 3b {}^{2} + 16ac + 3c {}^{2}$

Answer 2

19a^2 + 3b^2 -3c^2 +34ab -16ac