2{ 5[12+5 (500 - 100)+399]}
This is solved by breaking the equasion down.
2 { 5 [12 + 5 (500 - 100) + 399 ]}
2 { 5 [12 + 5 (400) + 399]}
2 { 5 [12 + 2000 + 399]}
2 { 5 [2411]}
2 {12055}
24110
Is this the answer you were looking for?
2(5(12+5(500−100)+399))=2(5(12+(5)(400)+399))=2(5(12+2000+399))=2(5(2012+399))=2(5)(2411)=(2)(12055)=24110