Question 897082


equation to simplify is -sqrt(125) + 3*sqrt(45)


sqrt(125) is equivalent to sqrt(5*25) which is equal to sqrt(25) * sqrt(5) which is equal to 5*sqrt(5).


sqrt(45) is equivalent to sqrt(5*9) which is equal to sqrt(5) * sqrt(9) which is equal to 3 * sqrt(5)


your original expression of -sqrt(125) + 3*sqrt(45) becomes:


-5 * sqrt(5) + 3 * 3 * sqrt(5). *****


factor out the common factor of sqrt(5) and combine 3*3 to get 9 and your equation becomes:


(-5 + 9) * sqrt(5)


combine like terms to get:


4 * sqrt(5)


if you did this correctly, then:


-sqrt(125) + 3*sqrt(45) should give you the same answer as 4 * sqrt(5)


-sqrt(125) + 3 * sqrt(45) is equal to 8.94427191...


4*sqrt(5) is equal to 8.94427191...


answers are the same, so the final expression is good.


i think you were right, but you didn't finish the job.


you had gotten:


-5 * sqrt(5) + 3 * 3 * sqrt(5)


that looks exactly like what i got at the point marked with *****


that's shown below again for your convenience.


-5 * sqrt(5) + 3 * 3 * sqrt(5). *****


what you got was an intermediate result.


you needed to finish the job by combining like terms and factor out the sqrt(5), etc. as i did above.