Can anyone help me with both problems please?
1 answer:
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Answer:
Step-by-step explanation:
The sum of the ages of a Mother and her son is 78 , three years ago the mother is five times as old as the son, what is their present ages?
To solve this , let the age of the mother be x and the age of the son be y , from the first statement :
x + y = 78
Three years ago , the mother will be x- 3 and the son will be y - 3 , from the second statement:
x - 3 = 5 ( y-3)
x- 3 = 5y - 15
x - 5y = -12
The resulting equations are
x + y = 78
x - 5y = -12
This is called a simultaneous linear equation , that means it is a linear equation.
The side of a square is xcm , if the difference between the area and the perimeter is 12 , find the legth of its side.
Interpretation:
The formula for the area of a square is and the perimeter is 4l , from the question , we have
- 4x = 12
This is not a linear equation , it is simply a quadratic equation , so the situation is non linear
Let us denote the number of tiles by 
.
In the first store, if Darin bought tiles, he would need to spend:
(measured in $)
In the second store, if Darin bought tiles, he would need to spend:
(measured in $)
For the cost to be the same at both stores, it means (measured in $)
Moving
over to the left hand side and changing signs:
tiles
Let's check. If he buys 60 tiles in the first store, he spends:
$0.79×60 + $24 = $47.40 + $24 = $71.40
If he buys 60 tiles in the second store, he spends:
$1.19×60 = $71.40
∴ Darin needs to buy 60 tiles for the cost to be the same at both stores.
In the first store, if Darin bought
In the second store, if Darin bought
For the cost to be the same at both stores, it means (measured in $)
Moving
Let's check. If he buys 60 tiles in the first store, he spends:
$0.79×60 + $24 = $47.40 + $24 = $71.40
If he buys 60 tiles in the second store, he spends:
$1.19×60 = $71.40
∴ Darin needs to buy 60 tiles for the cost to be the same at both stores.