# Week 4 – Precalc 11

For week 4 of Precalc 11, we had 3 lessons to finish off the unit. The first lesson was on adding and subtracting radicals, the second was on multiplying and dividing radicals, and the third and final lesson of the unit was on solving radical equations. There was lot’s of concepts and I learned at least 1 new thing each lesson.

For lesson 2.3 I learned that in order to add or subtract any radical expression, the coefficients can be different, but the radical must always remain the same, similar to the concept of adding and subtracting variables.

Example : 6 $\sqrt{5}$ + 4 $\sqrt{5}$ = 10 $\sqrt{5}$

For lesson 2.4 I learned that when multiplying radical expressions, the coefficients are multiplied or divided, as well as the radicands.

Example : 4 $\sqrt{3}$ x 5 $\sqrt{2}$ = 20 $\sqrt{6}$

For lesson 2.5 (final lesson), I learned about restrictions and how to find them, and the importance of using the concept, what you do to one side you must do to the other, in order to square both sides of an equation to get rid of square roots.

Example : If there is a variable under the root sign, the variable must be positive. $\sqrt{x}$ = 10, x >= 0.