Addd 4 to both sides

sqare both sides
x+9=25
minus 9 both sides
x=16
plug it in for x and see



1=1
true
not extraneous
an extraneous root would be x=-34
Answer:
Look at the equations:
y
=
−
9
x
−
21
and
y
=
5
x
+
7
Because both equations equal (y), they both equal the same.
If an equations says "
y
=
−
9
x
−
21
" , that means we can replace (y) with
−
9
x
−
21
.
Therefore when i take the equation:
y
=
5
x
+
7
, we can replace (y) to get:
−
9
x
−
21
=
5
x
+
7
Now isolate (x):
−
9
x
−
21
=
5
x
+
7
⇔
−
21
=
14
x
+
7
⇔
−
28
=
14
x
⇔
x
=
−
2
Distance=amount of gas times miles per gallon
distance=y
amount of gas=x
mpg=?
given
y=300
x=10
300=10 times ?
divide both sidesj by 10
30=?
equation is
y=x times 30 or
y=30x