Comparing Rectangle Areas: 30x×(4x+8) vs (7+27x)×5 in Fabric Production

Question

In a fabric factory, the possible sizes of fabric are:

30x×(4x+8) 30x\times(4x+8)

(7+27x)×5 (7+27x)\times5

How much more material does the factory need?

Video Solution

Solution Steps

00:00 Which measure requires more material?
00:03 Let's make sure to open parentheses properly
00:07 The factor will multiply each factor in parentheses
00:10 This is simplifying the first measure
00:13 We'll use the same method to simplify the second measure
00:25 Let's assume X equals 1
00:28 Let's substitute into the measures and see which is larger
00:37 In this case, the first measure
00:41 Now let's assume X equals one-tenth
00:45 Let's substitute into the measures and see which is larger
00:58 This is the first measure
01:05 This is the second measure
01:10 In this case, the second measure requires more material
01:16 Therefore, we cannot determine which measure requires more material

Step-by-Step Solution

We begin by simplifying the two exercises using the distributive property:

We start with the first expression.

30x×(4x+8)= 30x\times(4x+8)=

30x×4x+30x×8= 30x\times4x+30x\times8=

120x2+240x 120x^2+240x

We now address the second expression:

(7+27x)×5= (7+27x)\times5=

5×7+5×27x= 5\times7+5\times27x=

35+135x 35+135x

In order to calculate the expressions, let's assume that in each expression x is equal to 1.

We can now substitute the X value into the equation:

120x2+240x=120×12+240×1=120+240=360 120x^2+240x=120\times1^2+240\times1=120+240=360

35+135×1=35+135=170 35+135\times1=35+135=170

Hence it seems that the first expression is larger and requires more fabric.

Let's now calculate the expressions assuming that x is less than 1. We substitute this value into each of the expressions as follows:x=110 x=\frac{1}{10}

120100+24010=115+24=2515 \frac{120}{100}+\frac{240}{10}=1\frac{1}{5}+24=25\frac{1}{5}

35+13510=48.5 35+\frac{135}{10}=48.5

This time the second expression seems to be larger and requires more fabric.

Therefore, it is impossible to determine.

Answer

It is not possible to calculate.