x²+10x+16=0 x^2+10x+25=9 (x+5)^2=9所以 x+5=3 x=2 或 x+5=-3 x=-8 x²-x-¾=0x^2-x+1/4=1(x-1/2)^2=1所以x-1/2=1 x=3/2 或x-1/2=-1 x=-1/2
①:x²+10x+16=0 (x+2)(x+8)=0 x1=-2 x2=-8 ②:x²-x-¾=0 (x-3/2)(x+1/2)=0 x1=3/2 x2=-1/2 .