Chapter 10 QuadratiC EQuations 351Solve the equation by factoring.
xx^2 ++= 560
xx xx
xx
(^2560230)
20 30
22 3
++=++=
+= +=
−− −−
becomes( )( )
33
xx=− =− 23
Solve the equation by factoring.
x^2 + 7 x = 8
Before the factoring method can work, we must write the equation so that
0 is on one side, so we begin by subtracting 8 from each side.
xx
xx
2
2
78
88
780
+=
−−
+−=
xx xx
xx
(^2780810)
80 10
8
+−=+−=
+= −=
−−
becomes( )( )
8811
81
++
=− =
xx
Solve the equation by factoring.
x^2 − 16 = 0
You might notice that the nonzero side of this equation is the difference of
two squares, so x^2 − 16 becomes (x − 4)(x + 4). The equation x^216 = 0–
becomes (x − 4)(x + 4) = 0. Setting each of these factors equal to 0 gives us:
xx
xx
−= +=
+−−
==−
40 40
444
44
+ 4