Math online solver is one of the easiest ways for students to get help in math. Its growing popularity among students and parents is a testament to how effective it has been in helping students get math help in a fun and easy way. Math solver is very convenient as it give you a lot of flexibility in terms of time and place, which tutoring centers or after school programs cannot beat. The math solvers on the internet are experienced and qualified and being online, you get to select the best of them, wherever they may be. Math solver have solutions and lessons for students from K-12 to college.

Let the age of the son **3 years ago** = x years

Therefore age of his father = $x^2$

Step 1:

**Twelve years hence: **

Age of Son = x + 15

Therefore age of his father = $x^2$ + 15

Step 2:

The problem states :

Age of father = 2(age of his son)

=> $x^2$ + 15 = 2(x + 15)

=> x^{2} + 15 = 2x + 30

=> x^{2} - 2x = 30 - 15

=> x^{2} - 2x = 15

=> x^{2} - 2x - 15 = 0

**Step 3:**

Solve for x,

x^{2} - 2x - 15 = 0

=> x^{2} - 5x + 3x - 15 = 0

=> x(x - 5) + 3(x - 5) = 0

=> (x + 3)(x - 5) = 0

Step 4:

either x + 3 = 0 or x - 5 = 0

=> x = -3 (neglecting negative value)

or x = 5

=> x = 5, son's age**3 years ago**

Therefore father's age 3 years ago = 5^{2} = 25

So father's present age = 25 + 3 = 28

Thus, the present age of the father = 28 years.

Therefore age of his father = $x^2$

Step 1:

Therefore age of his father = $x^2$ + 15

Step 2:

The problem states :

Age of father = 2(age of his son)

=> $x^2$ + 15 = 2(x + 15)

=> x

=> x

=> x

=> x

x

=> x

=> x(x - 5) + 3(x - 5) = 0

=> (x + 3)(x - 5) = 0

Step 4:

either x + 3 = 0 or x - 5 = 0

=> x = -3 (neglecting negative value)

or x = 5

=> x = 5, son's age

Therefore father's age 3 years ago = 5

So father's present age = 25 + 3 = 28

Thus, the present age of the father = 28 years.

6x + 15y = 50 and 3x + 10y = 50

Given system of linear equations

6x + 15y = 50 ................................(1)

and

3x + 10y = 50 ..................................(2)

Step 2:

Multiply equation (2) by 2

=> 2(3x + 10y) = 2 * 50

=> 6x + 20y = 100 ...................................(3)

Step 3:

Solve (1) and (3):

Subtract equation( 3) from equation ( 1)

=> 6x + 15y - 6x - 20y = 50 - 100

=> - 5y = - 50

Divide each side by -5

=> y = 10

Step 4:

Put y = 10 in (1)

=> 6x + 15 * 10 = 50

=> 6x + 150 = 50

=> 6x = 50 - 150

=> 6x = - 100

Divide each side by 6, to isolate x,

=> x = $\frac{-100}{6}$

=> x = $\frac{-50}{3}$

Hence, the solution to the system, (x, y) = ($\frac{-50}{3}$, 10).