Respuesta :

[tex]\large\color{pink}{{★ƛƝƧƜЄƦ ↦}}[/tex]

[tex] \purple{ \bf{Let's \: solve→}}[/tex]

[tex] \sf{↪ {x}^{2} + 10x + 21} \\ \\ \sf{↪by \: splitting \: middle \: term} \\ \\ \sf{↪ {x}^{2} + 7x + 3x + 21} \\ \\ \sf{↪taking \: common} \\ \\ \sf{↪x(x + 7) + 3(x + 7)} \\ \\ \sf{↪(x + 3)(x + 7) \: is \: yr \: answer}[/tex]

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[tex]\sf{\:мѕнαcкεя\: ♪...}[/tex]