Answer: [tex]\bold{\dfrac{4}{49}z^2-\dfrac{12}{35}xz+\dfrac{9}{25}x^2}[/tex]
Step-by-step explanation:
[tex]\bigg(\dfrac{2}{7}z-\dfrac{3}{5}x\bigg)\bigg(\dfrac{2}{7}z-\dfrac{3}{5}x\bigg)\\\\\\=\dfrac{2}{7}z\bigg(\dfrac{2}{7}z-\dfrac{3}{5}x\bigg)-\dfrac{3}{5}x\bigg(\dfrac{2}{7}z-\dfrac{3}{5}x\bigg)\\\\\\=\dfrac{4}{49}z^2-\dfrac{6}{35}xz-\dfrac{6}{35}xz+\dfrac{9}{25}x^2\\\\\\=\dfrac{4}{49}z^2-\dfrac{12}{35}xz+\dfrac{9}{25}x^2[/tex]
