Question

subtract. write your answer in simples
$4\sqrt{28} - 3\sqrt{63}$

Explanation:

Step1: Simplify each square root

Simplify $\sqrt{28}$: $\sqrt{28}=\sqrt{4\times7}=2\sqrt{7}$ (since $\sqrt{4}=2$).
Simplify $\sqrt{63}$: $\sqrt{63}=\sqrt{9\times7}=3\sqrt{7}$ (since $\sqrt{9}=3$).

Step2: Substitute back into the expression

For $4\sqrt{28}$: $4\times2\sqrt{7}=8\sqrt{7}$.
For $3\sqrt{63}$: $3\times3\sqrt{7}=9\sqrt{7}$.

Step3: Perform the subtraction

Now, $8\sqrt{7}-9\sqrt{7}=(8 - 9)\sqrt{7}=-\sqrt{7}$.

Answer:

$-\sqrt{7}$