Ответы и объяснения

2013-11-28T15:17:38+04:00
9x^2-9x+4-7x^2 = 0
2
x^2 - 9x+4=0
D = 81 - 32 = 49
x1 = 9 -7 / 4 = 1/2 = 0.5
x2 = 9 +7/4 = 4