Answer: 46 years
Step-by-step explanation:
Let the father's age be x and the son's age be y, then 3 years ago:
Father = x - 3
son = y - 3
Then , from the first statement :
x - 3 = 3 ( y - 3 )
x - 3 = 3y - 9
x = 3y - 9 + 3
x = 3y - 6 .......................................... equation 1
In five years time
father = x + 5
son = y + 5
Then , from the second statement
x + 5 = 2 ( y + 5 )
x + 5 = 2y + 10
x = 2y + 10 - 5
x = 2y + 5 ........................ equation 2
Equating equation 1 and 2 , we have
3y -6 = 2y + 5
add 6 to both sides
3y = 2y + 5 + 6
subtract 2y from both sides
3y - 2y = 11
y = 11
substitute y = 11 into equation 1 to find the value of x
x = 3y - 6
x = 3(11) - 6
x = 33 - 6
x = 27
This means that the father is presently 27 years and the son is presently 11 years.
In four years time
father = 27 + 4 = 31
son = 11 + 4 = 15
sum of their ages in four years time will be
31 + 15 = 46 years
<h3>
Answer: Choice C. (1,0)</h3>
============================================================
Explanation:
Point H is at (-2,2) and J is at (4,-2)
Focusing on the x coordinates, the midpoint is (x1+x2)/2 = (-2+4)/2 = 1.
The y coordinates have a midpoint of (y1+y2)/2 = (2+(-2))/2 = 0.
The midpoint is at (1,0). That's why the answer is choice C.
--------------------------
This next section is optional.
Points I and K are located at (4,3) and (-2,-3) respectively
Averaging the x coordinates gets us (x1+x2)/2 = (4+(-2))/2 = 1
Doing the same for the y coordinates gets us (y1+y2)/2 = (3+(-3))/2 = 0
We end up with the same midpoint (1,0)
The midpoint being the same for both diagonals proves that each diagonal is bisected, ie cut in half.
Answer:
Definition: The enclosing boundary of a curved geometric figure, especially a circle.
Step-by-step explanation:
Answer:
x = 2
Step-by-step explanation:
These equations are solved easily using a graphing calculator. The attachment shows the one solution is x=2.
__
<h3>Squaring</h3>
The usual way to solve these algebraically is to isolate radicals and square the equation until the radicals go away. Then solve the resulting polynomial. Here, that results in a quadratic with two solutions. One of those is extraneous, as is often the case when this solution method is used.
The solutions to this equation are the values of x that make the factors zero: x=2 and x=-1. When we check these in the original equation, we find that x=-1 does not work. It is an extraneous solution.
x = -1: √(-1+2) +1 = √(3(-1)+3) ⇒ 1+1 = 0 . . . . not true
x = 2: √(2+2) +1 = √(3(2) +3) ⇒ 2 +1 = 3 . . . . true . . . x = 2 is the solution
__
<h3>Substitution</h3>
Another way to solve this is using substitution for one of the radicals. We choose ...
Solutions to this equation are ...
u = 2, u = -1 . . . . . . the above restriction on u mean u=-1 is not a solution
The value of x is ...
x = u² -2 = 2² -2
x = 2 . . . . the solution to the equation
_____
<em>Additional comment</em>
Using substitution may be a little more work, as you have to solve for x in terms of the substituted variable. It still requires two squarings: one to find the value of x in terms of u, and another to eliminate the remaining radical. The advantage seems to be that the extraneous solution is made more obvious by the restriction on the value of u.
The answer would be 3. {0,3}.
Remember: {x,y}
2(0)+3=3
0+3=3
0+3=3
