Question

resolva as expressões a)7x+(2-10x)-(x-4) b)x²-1,5x+2+(-x²+2,3x-6)

Answer 1

a) 7x +(2 -10x) -(x -4) = 
    7x +1 -10x -x +4 =
    7x -10x -x = -1 -4
    -3x -x = -5
    -4x = -5
       x = -5/-4
       x = 5/4


b) x² -1,5x +2+(-x² +2,3x -6) =
    x² -1,5x +2 -x² +2,3x -6 =
    x² -x² -1,5x +2,3x +2 -6 =       x² -x² se cancelam
    0,8x -4 =
    0,8x = 4
         x = 4/0,8
         x = 5