Solve left(a-bright)^2-4b^2

$${ \left(a-b \right) }^{ 2 } -4 { b }^{ 2 }$$

Evaluate

$$\left(a-3b\right)\left(a+b\right)$$

Solution Steps

Use binomial theorem \left(p-q\right)^{2}=p^{2}-2pq+q^{2} to expand \left(a-b\right)^{2}.

$$a^{2}-2ab+b^{2}-4b^{2}$$

Combine b^{2} and -4b^{2} to get -3b^{2}.

$$a^{2}-2ab-3b^{2}$$

Expand

$$a^{2}-2ab-3b^{2}$$

Solution Steps

Use binomial theorem \left(p-q\right)^{2}=p^{2}-2pq+q^{2} to expand \left(a-b\right)^{2}.

$$a^{2}-2ab+b^{2}-4b^{2}$$

Combine b^{2} and -4b^{2} to get -3b^{2}.

$$a^{2}-2ab-3b^{2}$$