6x + 8 dla x= - 2
6*(-2) + 8 = -12 + 8 = -4
[tex]3x^2 + 2x[/tex] dla x = 3
[tex]3*3^2 + 2*3 = 3*9 + 6 = 27 + 6 = 33[/tex]
[tex]5(x+2)^2[/tex] dla x= -4
[tex]5(-4+2)^2 = 5 *(-2)^2 = 5 * 4 = 20[/tex]
2x - 5y dla x = 5 y = -3
2*5 - 5*(-3) = 10 - (-15) = 10 + 15 = 25
3xy + 7 dla x = [tex]\frac{1}{2}[/tex] y = 8
[tex]3*\frac{1}{2} *8 + 7 = 12 + 7 = 19[/tex]
4x - 8 = 2x + 5
4x - 2x = 5 + 8
2x = 13
x = [tex]\frac{13}{2}[/tex]
x = [tex]6\frac{1}{2}[/tex]
8x = 5x + 9
8x - 5x = 9
3x = 9
x = 3
