Помогите срочно!!!Номер 623(2,4),632(5)!!!20б

623)2)[latex] frac{6.8 - 7 +8 }{5.4 - 6.7} \\ 5.4 - 6.7 = - 1.3\ 6.8-7+8 = 6.8 + 1 = 7.8\\ frac{6.8 - 7 +8 }{5.4 - 6.7} = frac{7.8}{-1.3} = -6[/latex]4)[latex] frac{0.6*(-9) - 3.6}{-1.5*4}\\ 0.6*(-9) - 3.6 = -5.4 -3.6 = -9\ -1.5*4 = -6\\ frac{0.6*(-9) - 3.6}{-1.5*4} = frac{-9}{-6} = 1.5 [/latex]632)2)[latex]b = 4\(9.3b-1.5b):(-6) = (9.3*4-1.5*4):(-6)=(37.2-6):(-6)=31.2:(-6)=-5.2[/latex][latex]\b = -5\(9.3b-1.5b):(-6) = (9.3*(-5)+1.5*5):(-6)=-39:(-6)=6.5[/latex]