Answer:
Step-by-step explanation:
( a - b ) ( a + b ) = a² - b²
[tex](x + 5)(x - 5)[/tex]
[tex] {x}^{2} - {5}^{2} [/tex]
[tex] = {x}^{2} - 25[/tex]
ㅤㅤ2. formula:
( x + y )³ = x³ + 3x²y + 3xy² + y³
[tex](4b + 9) {}^{3} [/tex]
[tex](4b) {}^{3} + 3 \times (4b) {}^{2} \times 9 + 3 \times 4b \times {9}^{2} + 9 {}^{3} [/tex]
[tex]64 {b}^{3} + 3 \times (4b) {}^{2} \times 9 + 3 \times 4b \times {9}^{2} + {9}^{3} [/tex]
[tex]64 {b}^{3} + 3 \times 16 {b}^{2} \times 9 + 3 \times 4b \times {9}^{2} + {9}^{3} [/tex]
[tex]64 {b}^{3} + 3 \times 16 {b}^{2} \times 9 + 3 \times 4b \times 81 + {9}^{3} [/tex]
[tex]64 {b}^{3} + 3 \times 16 {b}^{2} \times 9 + 3 \times 4b \times 81 + 729[/tex]
[tex]64 {b}^{3} + 432 {b}^{2} + 3 \times 4b \times 81 + 729[/tex]
[tex] = 64 {b}^{3} + 432 {b}^{2} + 972b + 729[/tex]
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