Evaluate
\[ (1.5x^2 – 0.3y^2)(1.5x^2 + 0.3y^2) \]
Solution:
Using identity:
\[ (a-b)(a+b)=a^2-b^2 \]
\[ (1.5x^2 – 0.3y^2)(1.5x^2 + 0.3y^2) \]
\[ = (1.5x^2)^2 – (0.3y^2)^2 \]
\[ = 2.25x^4 – 0.09y^4 \]
\[ (1.5x^2 – 0.3y^2)(1.5x^2 + 0.3y^2) \]
Using identity:
\[ (a-b)(a+b)=a^2-b^2 \]
\[ (1.5x^2 – 0.3y^2)(1.5x^2 + 0.3y^2) \]
\[ = (1.5x^2)^2 – (0.3y^2)^2 \]
\[ = 2.25x^4 – 0.09y^4 \]