Given:
The width of a kitchen is 4.2 metres.
Kitchen cupboard widths are 60 cm.
To find:
The number of kitchen cupboard that will fit in 4.2 metres.
Solution:
Let x be the number of kitchen cupboard that will fit in 4.2 metres.
Width of 1 cupboard = 60 cm
Width of x cupboards = 60x cm
We know that, 1 m = 100 cm.
Width of a kitchen = 4.2 metres
= 4.2×100 cm
= 420 cm
Now, the width of the x cupboards is equal to width of the kitchen.
Therefore, the number of kitchen cupboard that will fit in 4.2 metres is 7.
The correct answer to this problem is D.
With the given information, we can create several equations:
120 = 12x + 2y
150 = 10x + 10y
With x being the number of rose bushes, and y being the number of gardenias.
To find the values of the variables, we can use two methods: Substitution or Elimination
For this case, let us use elimination. To begin, let's be clear that we are going to be adding these equations together. Therefore, in order to get the value of one variable, we must cancel one of them out - it could be x or y, it doesn't matter which one you decide to cancel out. Let's cancel the x out:
We first need to multiply the equations by numbers that would cause the x's to cancel out - and this can be done as follows:
-10(120 = 12x + 2y)
12(150 = 10x + 10y) => Notice how one of these is negative
Multiply out:
-1200 = -120x - 20y
+ 1800 = 120x + 120y => Add these two equations together
---------------------------------
600 = 100y
Now we can solve for y:
y = 6
With this value of y known, we can then pick an equation from the beginning of the question, and plug y in to solve for x:
120 = 12x + 2y => 120 = 12x + 2(6)
Now we can solve for x:
120 = 12x + 12 => 108 = 12x
x = 9
So now we know that x = 9, and y = 6.
With rose bushes being x, we now know that the cost of 1 rose bush is $9.
With gardenias being y, we now know that the cost of 1 gardenia is $6.
If the function is:
f (x ) = 5 ( x +2 ) / ( 3 ( x-1 ) ( x - 7) then for: f ( x ) = 0
5 ( x + 2 ) = 0
x + 2 = 0
x = -2
Answer: E ) -2 ( only )
