Elementary Algebra

2$a^{2}$ - 4$b^{2}$ = We substitute a = 0.2 and b = -0.3 into the expression and simplify: 2 $\times$$(0.2)^{2}$ - 4 $\times$ $(-0.3)^{2}$ = 2 $\times$ 0.04 - 4 $\times$ 0.09 = 0.08 - 0.36 = -0.28