Question #4cac8

If you let the cost of the dryer be #x#, then the cost of the washer can be writted #x-81#.

Since the total cost is $769, we add the two prices:

#x+(x-81) = 769#

We combine the like terms (the two #x# terms)

#2x-81 = 769#

Add 81 to each side (to continue combining like terms)

#2x = 850#

Divide each side by 2:

#x=425#

So, the dryer is $425 and the washer is $81 less, or $344.

To find out both of the prizes, one can make a formula!

We have 2 variables which are unknown: the prize of the dryer (called x) and the prize of the washer (called y).

Now we know the variables we only need the function! So what we know is that the prizes summed up equals 769$. We can state that as

#769= x + y# function (1)

What we also know is that the prize of the washer is 81$ lower than the prize of the drying. This can be stated as:

#y = x - 81# function (2)

Since solving for 1 variable is much easier, we will take that approach! This can be down by a substitution: we replace the #y# in function (1) with the function (2). So we get a new line with only x as variable!

#769 = x+(x-81)#

Then we use the calculation rules to find #x#
#769=x+x-81#
#769=2x-81#
#850=2x#
#x= 425#

So now we have found the value of #x# which is the prize of the dryer (425$). To get the prize of the washer we use again function (2) and fill in the value of #x# (425)

#y= 425-81#
#y= 344#

So the prize of the washer is 344$.
You can check this result by adding both prizes!
#x + y = 344+425=769 #