Question

Упростите выражение : 2a(3a-5)-(a-3)(a-7)​

Answer 1

$2a(3a - 5) - (a - 3)(a - 7) = 2a times 3a - 2a times 5 - (a times a -a times 7 - 3 times a + 3 times 7) = \ = 6 {a}^{2} - 10a - ( {a}^{2} - 7a - 3a + 21) = \ = 6 {a}^{2} - 10a - {a}^{2} + 7a + 3a - 21 = \ = 5 {a}^{2} - 21$