Oblicz wartość liczbową wyrażenia 3a do kwadratu + ab - b dla a -1/2, b 2 3(m - n) - (2m+n) + (2n - 1) + 2 dla m -2, n 1

3a^2 + ab - b = (-1/2)^2 + (-1/2) * 2 - 2 = -1/4 + (-1/4) - 2 = -2/4 - 2 = -1/2 - 2 = -2 1/2 3(m - n) - (2m + n) + (2n - 1) + 2 = 3m - 3n - [2 * (-2) - 1] + 2 = -6 + 3 - (-4 - 1) + 2 = -3 + 5 + 2 = 4

[latex]3a^2+ab-b=\a=-0,5\b=2\3(-0,5)^2+(-0,5)*2-2=3*0,25-1-2=0,75-3=-2,25\\3(m-n)-(2m+n)+(2n-1)+2=\m=-2\n=1\\ 3(-2-1)-(2*(-2)+1)+(2*1-1)+2=\=3*(-3)-(-3)+1+2=\=-9+3+3=-3[/latex]