Radical 8 plus radical 18

5√2

Step-by-step explanation:

√8 + √18

We first have to find what is the largest perfect square that goes into √8:

4 is the largest, so therefore → √8 gives you 2√2:

Work: √4 * √2 → 2 * √2 → 2√2

Now we have to find what is the largest perfect square that goes into √18:

9 is the largest, so therefore → √18 gives you 3√2:

Work: √9 * √2 → 3 * √2 → 3√2

Because 2√2 and 3√2 have the same "base" of √2, they can be added together:

2√2 + 3√2 = 5√2 (The "bases" are to be left alone!)