Simplify. (asqrt8)-(3sqrt(2a^2)) if it can be simplified.?

Question

Also,
Factor -21x^3 + 49x^2

Can you show me how this is done. I'm quite stuck. Thank You :)

Answer 1

(asqrt8)-(3sqrt(2a^2))
=2asqrt(2) - 3asqrt(2)
=-a sqrt(2)

-21x^3 + 49x^2
=-7x^2(3x - 7)

Answer 2

(asqrt8)-(3sqrt(2a^2))
=a√8 - 3√(2a² )
=2√2 a - 3√2 a
= -1√2 a
= -√2 a OR - a √2

-21x^3 + 49x^2
common factor 7x^2
= 7x^2(-3x + 7)

Answer 3

8 = 2*2^2 so sqrt8 = 2*sqrt2
sqrt(2a^2) = abs(a)sqrt(2) (asqrt2 if a is positive, -asqrt2 if a is negative)

so asqrt8-3sqrt(2a^2) = 2asqrt2 - 3abs(a)sqrt2
which is -asqrt2 if a is positive
and 5asqrt2 if a is negative
-21x^3 + 49x^2 : you can factor x^2 because x^3 = x*x^2
you get x^2(49-21x). you can go further because 49=7*7 and 21=7*3.
the final expression is 7x^2(7-3x)

Answer 4

3sqrt(2a^2)=3sqrt(2)sqrt(a^2)=3asqrt(2)

asqrt(8)=asqrt(4x2)=asqrt(4)sqrt(2)=2asqrt(2)

So we have 2asqrt(2)-3asqrt(2)= -asqrt(2)

For the second one, the greatest common factor of x^2 and x^3 is x^2, and the gcf of 21 and 49 is 7, so take both of those out and leave the remaining quantity in parenthesis.

Answer 5

-21x^3 + 49x^2
factor out -7x^2
-7x^2(3x - 7)

(asqrt8)-(3sqrt(2a^2))
square root of 8 = square root of 4 times square root of 2
square root of 4 = 2
so you have 2 times square root of 2
square root of a^2 = a
(2asqrt2)-(3asqrt2)
now that it is from the same sqrt, you can subtract
-asqrt2

Answer 6

?? what the hell!