If
a
b
=

c
d
then, a × d = b × c

If
a
b
=

c
d
then, a × d = b × c

Solve for x if
5
x

=
10
16

The proportion becomes
5
8

=
10
16

5
x

=
10
16

Solve for n if
8
10

=
n
25

200
10

=
10n
10

If
a
b

=
c
d
then,

a + b
b

=
c + d
d

x  8
8

=
6
4

x  8 + 8
8

=
6 + 4
4

x
8

=
10
4

If
x
y

=
x
4
then, y = 4

For instance If
50
y

=
50
100
then, y = 100

If
18
y

=
x
y
then, x = 18

If
a
b

=
c
d
then,

a + c
b + d

=
a
b

a + c
b + d

=
a
b

Say you have
x + 2
8 + 4

=
x
8

It is equivalent to
x
8

=
2
4

Solve for x if
5
x

=
10
16

The proportion becomes
5
8

=
10
16

5
x

=
10
16

Solve for n if
8
10

=
n
25

200
10

=
10n
10

If
a
b

=
c
d
then,

a + b
b

=
c + d
d

x  8
8

=
6
4

x  8 + 8
8

=
6 + 4
4

x
8

=
10
4

If
x
y

=
x
4
then, y = 4

If
50
y

=
50
100
then, y = 100

If
18
y

=
x
y
then, x = 18

If
a
b

=
c
d
then,

a + c
b + d

=
a
b

a + c
b + d

=
a
b

Say you have
x + 2
8 + 4

=
x
8

It is equivalent to
x
8

=
2
4

Jul 03, 20 09:51 AM
factoring trinomials (ax^2 + bx + c ) when a is equal to 1 is the goal of this lesson.
Basic math formulas
Algebra word problems
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.