3、负5、7、12算24点,很急,好的追加分

(7-(-5))*3-12=24((7-(-5))*3)-12=24(-5)-7+3*12=24((-5)-7)+3*12=24(-5)-7+(3*12)=24((-5)-7)+(3*12)=24(-5)-(7-3*12)=24(-5)-(7-(3*12))=24(-5)-7+12*3=24((-5)-7)+12*3=24(-5)-7+(12*3)=24((-5)-7)+(12*3)=24(-5)-(7-12*3)=24(-5)-(7-(12*3))=24(-5)+3*12-7=24(-5)+(3*12)-7=24((-5)+3*12)-7=24(-5)+(3*12-7)=24((-5)+(3*12))-7=24(-5)+((3*12)-7)=24(-5)+12*3-7=24(-5)+(12*3)-7=24((-5)+12*3)-7=24(-5)+(12*3-7)=24((-5)+(12*3))-7=24(-5)+((12*3)-7)=243*(7-(-5))-12=24(3*(7-(-5)))-12=243*12-7+(-5)=24(3*12)-7+(-5)=24(3*12-7)+(-5)=24((3*12)-7)+(-5)=243*12-(7-(-5))=24(3*12)-(7-(-5))=243*12+(-5)-7=24(3*12)+(-5)-7=243*12+((-5)-7)=24(3*12+(-5))-7=24(3*12)+((-5)-7)=24((3*12)+(-5))-7=2412*3-7+(-5)=24(12*3)-7+(-5)=24(12*3-7)+(-5)=24((12*3)-7)+(-5)=2412*3-(7-(-5))=24(12*3)-(7-(-5))=2412*3+(-5)-7=24(12*3)+(-5)-7=2412*3+((-5)-7)=24(12*3+(-5))-7=24(12*3)+((-5)-7)=24((12*3)+(-5))-7=24