Câu hiện phép tính: 1) 5x(5-x)+(x+1)(5x-3) 2) (x-3)^2-(x-2)(x+2)+12x . 3) (1)/(2)

1) For the first expression, we need to apply the distributive property (a(b + c) = ab + ac) and then combine like terms. <br /> - $5x(5-x)$ becomes $25x - 5x^2$<br /> - $(x+1)(5x-3)$ becomes $5x^2 + 5x - 3x - 3$ which simplifies to $5x^2 + 2x - 3$<br /> - Combining these results in $25x - 5x^2 + 5x^2 + 2x - 3$ which simplifies to $27x - 3$<br /><br />2) For the second expression, we need to expand the squared term and the product, then combine like terms.<br /> - $(x-3)^2$ expands to $x^2 - 6x + 9$<br /> - $(x-2)(x+2)$ expands to $x^2 - 4$<br /> - Combining these with $12x$ gives $x^2 - 6x + 9 - x^2 + 4 + 12x$ which simplifies to $6x + 13$<br /><br />3) The third expression is a fraction and does not require any operations. It remains $\frac{1}{2}$