Question

HEEEEEELLLLLPPPPP ...... Pls help with this worksheet

Answer 1

First you identify a,b,c which is: a=2, b=0, c=0
and plug those numbers into the quadratic formula.

Answer 2

I believe the idea is to use a different strategy than Karen's.
The quadratic formula applies to almost any quadratic equations, but very often not as fast if other (easier) methods are available, such as the given problem.

We can also solve the given problem 2x^2=200 by factoring.
Transpose the constant 200 to the left to form an equation of the form:
2x^2-200=0
First extract the common factor 2
2(x^2-100)=0
by the property of zero product, either 2=0 or (x^2-100)=0.
Since 2 ≠ 0, we conclude that
(x^2-100)=0
which means
(x+10)(x-10)=0  (by the difference of two squares, x^2 and 10^2.
Again, by the property of zero product, either
(x+10)=0, or (x-10)=0 or both.
Solving both equations gives us
x=-10, or x=+10