Verified answer

Réponse:

Bonjour

Explications étape par étape:

[tex] \sqrt{18} = \sqrt{ {3}^{2} \times 2} = \sqrt{ {3}^{2} } \times \sqrt{2} = 3 \sqrt{2} \\ \sqrt{72} = \sqrt{9 \times 8} \\ = \sqrt{9} \times \sqrt{8} \\ = \sqrt{ {3}^{2} } \times \sqrt{ {2}^{3} } \\ = 3 \times 2 \sqrt{2} \\ = 6 \sqrt{2} \\ nous \: dirons \: donc \: \\ \sqrt{18} + 2 \sqrt{72} \\ = 3 \sqrt{3} + 2 \times 6 \sqrt{2} \\ = 3 \sqrt{3} + 12 \sqrt{2} \\ = 3 \sqrt{2} + 12 \sqrt{2} \\ = (3 + 12) \sqrt{2} \\ = 15 \sqrt{2} [/tex]