tolong bantu yah mksih sblmnya...

|a|=4   ⇒  a² = |a|² = 4² = 16
|b|=6   ⇒  b² = |b|² = 6² = 36

a+b = 12 >>( a+b)²  = 12²  = 144

a²+2ab+b² = 144
16+2ab+36 = 144
52+2ab=144
2ab = 144-52
2ab = 92

|a-b|² = (a-b)² = a²-2ab+b² = 16 - 92 + 36 =  -40