El sistema de ecuaciones es: \( \left\{\begin{array}{c}h+m+k=20 \\ h+m=3 k \\ m+1=h\end{array}\right. \)

Identify the solutions of \( 3+4 \sqrt[3]{x^{2}-13}=-5 \). (1 point) \( \begin{array}{l}2 \sqrt{3},-2 \sqrt{3} \\ \sqrt{13},-\sqrt{13} \\ \sqrt{5},-\sqrt{5} \\ \sqrt{21},-\sqrt{21}\end{array} \)

1. Realiza las siguientes multiplicaciones. a. \( \frac{2}{3} x \cdot\left(6 x^{2}-5 x+\frac{1}{2}\right) \) b. \( 5 a \cdot\left(3 a^{2}-2 a b+7 b^{2}\right) \) c. \( (4 m-2 n)(3 m+9 n) \) d. \( (8 x-3)\left(x^{2}-5 x+6\right) \)

Factorise fully \( 2 x^{2}+13 x+15 \)

Write the following in simplified radical form. \( \sqrt[4]{y^{5}} \)

Factorise fully the expression \( 7 t^{2}+2 t-9 \)