How do you solve #-7n^2=-448#?

2 Answers
Sep 1, 2016

Answer:

#n=+-8#

Explanation:

Divide both sides by -7 so as to isolate the #n^2# term.

#(cancel(-7)^1 n^2)/cancel(-7)^1=(cancel(-448)^(64))/cancel(-7)^1rArrn^2=64#

now take the square root of both sides

#sqrt(n^2)=+-sqrt64rArrn=+-8#

Sep 1, 2016

Answer:

#n= 8 or n = -8#

Explanation:

This is a quadratic equation, it can be solved by factorising.

#-7n^2 = -448 larr div" "-7 # to simplify. Divide on both sides.

#n^2 = 64 larr # make it =0

#n^2 -64 larr # difference of two squares.

#(n+8)(n-8) = 0#

Either factor can be equal to 0.

If #n+8 = 0 rarr n = -8#

If #n-8 = 0 rarr n = 8 #