X-3=2x+10; x-2x=10+3; -x=13; x=13/(-1)= -13. Ответ: x= -13.
7.8(х+1)-11(3-2х) = 7.8х+7.8-33+22х = 29.8х - 26.2
Ответ:
232а
3x^2+15x-7=0
D = 15^2 - 4*3*(-7) = 309
x1 = (-15-√309)/(2*3) = -2.5 - √309 / 6 ≈ -5.4
x2 = (-15+√309)/(2*3) = -2.5 + √309 / 6 ≈ 0.4
232б
-2x^2-11x+3=0
2x^2+11x-3=0
D=11^2-4*2*(-3)=145
x1 = (-11-√145)/(2*2) = (-11-√145) / 4 ≈ -5.8
x2 = (-11+√145)/(2*2) = (-11+√145) / 4 ≈ 0.3
233
x^2 - 1000x + 89199 = 0
D = 1000^2 - 4*89199 = 643204 = 802^2
x наим = (1000 - √643204) / 2 = (1000 - 802) / 2 = 99