\( 1-Ham\,\, so\,\, bac\,\, hai\,\, co\,\,dang\,\, y=ax^2+b(a\ne 0)\\\to B\\2-Pt\,\, co\,\, nghiem\,\, x=2\\\to 4m-6+2m+1=0\\↔6m=5\\↔m=\dfrac{5}{6}\\3-Δ=7^2-4.3.(-1)=61>0\\→Pt\,\, co\,\, 2\,\, nghiem\,\, phan\,\, biet\,\,\\ Theo Viet: x_1+x_2=\dfrac{-b}{a}=\dfrac{-7}{3}\)