Find X in Rectangle: Area 40 cm² with Side Length 2x+4

Question

Rectangle ABCD has an area of

40 cm².

Side BC is equal to 5 cm.
Work out the value of x.

00:13 Let's find the value of X.

00:16 First, we'll use the formula for the area of a rectangle.

00:20 Multiply side A-B by side B-C.

00:24 Now, plug in the numbers and solve for X.

00:29 Be sure to open the parentheses carefully.

00:35 Next, let's isolate X.

00:39 And there you go, that's how we find the solution!

Let's multiply side AB by side BC

We'll set up the data as follows:

$5(2x+4)=40$

Let's multiply 5 by each term in parentheses:

$10x+20=40$

We'll move 20 to the right side and change its sign accordingly:

$10x=40-20$

Now we get:

$10x=20$

Let's divide both sides by 10:

$x=2$