Даны векторы 𝑎 → ( 7 ; 9 ) ${\displaystyle \stackrel{\to }{a}\left(7;9\right)}$ и 𝑏 → ( 8 ; − 6 ) . ${\displaystyle \stackrel{\to }{b}\left(8;-6\right).}$ Найдите скалярное произведение 𝑎 → ⋅ 𝑏 → . ${\displaystyle \stackrel{\to }{a}\cdot \stackrel{\to }{b}.}$