Dijawab ya bang... Maaf kalau gambar coret corey

[tex]\displaystyle \int\limits^2_{-1}ax^2-6x+5\,dx=15\\\left\frac a3x^3-3x^2+5x\right|^2_{-1}=15\\\frac a3(2^3-(-1)^3)-3(2^2-(-1)^2)+5(2-(-1))=15\\\frac a3(8+1)-3(4-1)+5(2+1)=15\\3a-9+15=15\\3a=9\\\boxed{\boxed{a=3}}[/tex]

jawaban C, cara ada difoto