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
You can just plug in one of the points to each equation until you get an equality that is true.
I chose to use (-3,2)
1. 5x+3y=1
5(-3)+3(2)=1
(-15)+ 6 = 1
(-9) = 1 <<<(FALSE)
2. x+5y=3
(-3)+5(2)= 3
(-3)+10= 3
7=3 <<<(FALSE)
3. 3x+5y=1
3(-3) + 5(2)= 1
(-9)+10=1
1=1<<<(TRUE)
So, the correct equation is 3x+5y=1.
Make sense?
Answer:
3
Step-by-step explanation:
just plug in 9 to b
9x2=18 18-15=3
Answer:
A
Step-by-step:
a^2+ b^2 = c^2
if we try A
6^2+8^2 = 10^2 => 64+36 = 100
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