Question

помогите пожалуйста
$(3 - y) \times (3 + y) \times (9 + y) {?}^{2}$
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Answer 1

$(3 - y)(3 + y)(9 + y) {}^{2} = (9 - {y}^{2})(81 + 18y + {y}^{2} ) = 729 + 162y + 9 {y}^{2} - 81y {}^{2} - 18 {y}^{3} - {y}^{4} = - {y}^{4} - 18y {}^{3 } - 72 {y}^{2} + 162y + 729$