Question

What should be taken away from 3x^2 - 4y^2+5xy + 20 to obtain - x^2 + 2x + 5




Plz solve it carefully

Answer 1

$(3 {x}^{2} - 4 {y}^{2} + 20 ) - a = - {x}^{2} + 2x + 5 \\ a = 3 {x}^{2} - 4 {y}^{2} + 20 + {x}^{2} - 2x - 5 \\ a = 4 {x}^{2} - 4 {y}^{2} + 15$
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