[tex]2.6 \times {10}^{3} + 1.8 \times {10}^{3} \\ = (2.6 + 1.8) \times {10}^{3} \\ = 4.4 \times {10}^{3} \\ = 4400[/tex]
[tex]9 \sqrt{24} \div \sqrt{18} \\ = 9 \sqrt{2 \times 2 \times 2 \times 3} \div \sqrt{2 \times 3 \times 3} \\ = 9 \times 2 \sqrt{2 \times 3} \div 3 \sqrt{2} \\ = \frac{18 \times \sqrt{2} \times \sqrt{3}}{3 \times \sqrt{2} } \\ = 6 \sqrt{3} [/tex]
[tex](4 \sqrt{6} - 2 \sqrt{7} )( 4\sqrt{6} + 2 \sqrt{7} ) \\ = {(4 \sqrt{6}) }^{2} - {(2 \sqrt{7}) }^{2} \\ = (4 \times 4 \times \sqrt{6} \times \sqrt{6} ) - (2 \times 2 \times \sqrt{7} \times \sqrt{7} ) \\ = (16 \times 6) - (4 \times 7) \\ = 96 - 28 \\ = 68[/tex]
Hope it helps
ray4918 here to help.
