А)ײ-5√2×+12=0 D=50-4*12=2 x1=(5√2-√2)/2 x2=(5√2+√2)/2 б)ײ+2√3-72=0 D=12+4*72=300 x12=(-2√3+-√300)/2 в)у²-6у+7=0 D=36-4*7=4 y1=(6-2)/2=2 y2=(6+2)/2=4 г)р²-10р+7=0 D=100-4*7=68 x12=(10+-√68)/2