surds

Question	Answer
what is a surd?	irrational square roots ( not even and don't work out straight away) e.g.√20
what is √28 simplified	√28 = √4 x 7 = √4 x √7 = 2 √7 we got the two in the end because 2 times 2 is 4, so 4 is a factor and we originally got 4 and 7 because 4 times 7 equals 28
work out: 3√20	3√20 = 3√4 x 5 = 3√4 x √5 = 3 x 2√5 = 6√5 keep the 3 in the front of the equation until the end, then multiply it with the number OUTSIDE the root only
what numbers do u divide to get the square root number?	3√20 = 3√4 x √5 in this we are talking about the numbers 4 and 5 one of them has to be one of the following numbers in this list: 4 ,9 ,16 ,25 ,36 ,49 ,64 ,81,100 ,121 in this equation we chose 4 because it fit in trying to equal 20
unsimplièfy this surd 3√2	3√2 = √9 x √2 = √9 x 2 = √18 doit backwards to what you normally would
what is a like surd?	a surd with the same number in the square root e.g. 7√3 + 5√3
figure out this like surd 2√3 + 4√3	2√3 + 4√3 = 6√3 you simplify add the outside numbers
work out this NOT LIKE surd 5√2 - √8	5√2 - √8 = 5√2 - √4 x √2 = 5√2 - 2√2 =3√2 you get the first surd and times it at the back of the equation

Resource summary

	Created by evie yallouz almost 7 years ago