Question

25. 7\(\sqrt{x}\)- 6x- 2

26.\(x^2\)-\(\sqrt{x}\)+x -1

27. 2a - 5\(\sqrt{ab}\)+ 3b

28.\(\sqrt{ab}\)+2\(\sqrt{a}\)+ 3\(\sqrt{b}\)+6

Answer 1

26: \(x^2-\sqrt{x}+x-1\)

\(=\sqrt{x}\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)+\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)\)

\(=\left(\sqrt{x}-1\right)\left(x\sqrt{x}+x+\sqrt{x}+\sqrt{x}+1\right)\)

\(=\left(\sqrt{x}-1\right)\left(x\sqrt{x}+x+2\sqrt{x}+1\right)\)

Answer 2

25: Ta có: \(-6x+7\sqrt{x}-2\)

\(=-6x+3\sqrt{x}+4\sqrt{x}-2\)

\(=-3\sqrt{x}\left(2\sqrt{x}-1\right)+2\left(2\sqrt{x}-1\right)\)

\(=\left(2\sqrt{x}-1\right)\left(2-3\sqrt{x}\right)\)

27: Ta có: \(2a-5\sqrt{ab}+3b\)

\(=2a-2\sqrt{ab}-3\sqrt{ab}+3b\)

\(=2\sqrt{a}\left(\sqrt{a}-\sqrt{b}\right)-3\sqrt{b}\left(\sqrt{a}-\sqrt{b}\right)\)

\(=\left(\sqrt{a}-\sqrt{b}\right)\left(2\sqrt{a}-3\sqrt{b}\right)\)

28: Ta có: \(\sqrt{ab}+2\sqrt{a}+3\sqrt{b}+6\)

\(=\sqrt{a}\left(\sqrt{b}+2\right)+3\left(\sqrt{b}+2\right)\)

\(=\left(\sqrt{b}+2\right)\left(\sqrt{a}+3\right)\)