25a^2-b^2 e 81j^2-k^2 x x^2-81y^2 25p^2-36q^2 h 4d^2-25e^2 Fully factorise: f s^2t^2-9 16x^2-49y^2 8x^2-2 49x^2-y^2z^2 p 12-27x^2 2y^2-8x^2 d 9a-16a^3

Let's factorize each expression step by step:1. - This is a difference of squares: \( (5a)^2 - b^2 \) - Factor as: \((5a - b)(5a + b)\)2. - This is a difference of squares: \((9j)^2 - k^2\) - Factor as: \((9j - k)(9j + k)\)3. - This is a difference of squares: \(x^2 - (9y)^2\) - Factor as: \((x - 9y)(x + 9y)\)4. - This is a difference of squares: \((5p)^2 - (6q)^2\) - Factor as: \((5p - 6q)(5p + 6q)\)5. - This is a difference of squares: \((2d)^2 - (5e)^2\) - Factor as: \((2d - 5e)(2d + 5e)\)6. - This is a difference of squares: \((st)^2 - 3^2\) - Factor as: \((st - 3)(st + 3)\)7. - This is a difference of squares: \((4x)^2 - (7y)^2\) - Factor as: \((4x - 7y)(4x + 7y)\)8. - Factor out the common factor: \(2(4x^2 - 1)\) - Recognize that is a difference of squares: \((2x)^2 - 1^2\) - Factor as: \(2(2x - 1)(2x + 1)\)9. - This is a difference of squares: \((7x)^2 - (yz)^2\) - Factor as: \((7x - yz)(7x + yz)\)10. - Factor out the common factor: \(3(4 - 9x^2)\) - Recognize that is a difference of squares: \(2^2 - (3x)^2\) - Factor as: \(3(2 - 3x)(2 + 3x)\)11. - Factor out the common factor: \(2(y^2 - 4x^2)\) - Recognize that is a difference of squares: \(y^2 - (2x)^2\) - Factor as: \(2(y - 2x)(y + 2x)\)12. - Factor out the common factor: \(a(9 - 16a^2)\) - Recognize that is a difference of squares: \(3^2 - (4a)^2\) - Factor as: \(a(3 - 4a)(3 + 4a)\)So, the fully factorized forms are:1. \((5a - b)(5a + b)\)2. \((9j - k)(9j + k)\)3. \((x - 9y)(x + 9y)\)4. \((5p - 6q)(5p + 6q)\)5. \((2d - 5e)(2d + 5e)\)6. \((st - 3)(st + 3)\)7. \((4x - 7y)(4x + 7y)\)8. \(2(2x - 1)(2x + 1)\)9. \((7x - yz)(7x + yz)\)10. \(3(2 - 3x)(2 + 3x)\)11. \(2(y - 2x)(y + 2x)\)12. \(a(3 - 4a)(3 + 4a)\)