Question

solucion (3+4+2+1) x (3+4+2+1) = 7x2+6x9+8x4

Answer 1

$(3 + 4 + 2 + 1) \times (3 + 4 + 2 + 1) = \\ (10) \times (10) = 100 \\ \\ - - - - - - - - - \\ \\ 7 \times 2 + 6 \times 9 + 8 \times 4 = \\ 14 + 54 + 32 = 100$

espero haberte ayudado