How do you solve #49x^2 - 64 = 0#?

2 Answers
Jun 27, 2016

Answer:

#x= 8/7 or x= -8/7#

Explanation:

#49x^2-64=0 or (7x)^2-(8)^2=0 or (7x+8)(7x-8)=0 :. (7x-8)=0 or (7x+8)=0 :.x= 8/7 or x= -8/7#[Ans]

Jun 27, 2016

Answer:

#x = =8/7 or x = -8/7#

Explanation:

Usually we make a quadratic equal to 0 to be able to solve it.
This is an exception, where we can use the normal method of x on one side and the numbers on the other.

#49x^2 = 64 #

#x^2 = 64/49 " find the square root of both sides"#

#x = +-sqrt(64/49)#

#x = =8/7 or x = -8/7#

However, we can also use the factorising method:

#49x^2 - 64 = 0 " the difference of two squares"#

#(7x + 8)(7x - 8)=0#

#x = -8/7 or x = 8/7#