Respuesta:
3[4(3 – 4) + 5(8 - 2) + (5 – 7) +6] + 3(5 - 6)
3×(4×−1+5×(8−2)+5−7+6)+3×(5−6)
3×(4×−1+5×6+5−7+6)+3×(5−6)
3×(−4+5×6+5−7+6)+3×(5−6)
3×(−4+30+5−7+6)+3×(5−6)
3×(26+5−7+6)+3×(5−6)
3×(31−7+6)+3×(5−6)
3×(24+6)+3×(5−6)
3×30+3×(5−6)
3×30+3×−1
90+3×−1
90−3
87