3.if A+b=10 And Ab=16 Find The Value Of A^(2)-ab+b^(2) And A^(2)+ab+b^(2)

3 min read Jul 25, 2024
3.if A+b=10 And Ab=16 Find The Value Of A^(2)-ab+b^(2) And A^(2)+ab+b^(2)

Solving the System of Equations: Finding the Values of $a^2 - ab + b^2$ and $a^2 + ab + b^2$

Given the system of equations:

$a + b = 10 \tag{1}$ $ab = 16 \tag{2}$

We are asked to find the values of $a^2 - ab + b^2$ and $a^2 + ab + b^2$.

Step 1: Solve for $a$ and $b$

From equation $(1)$, we can express $b$ in terms of $a$:

$b = 10 - a \tag{3}$

Substitute equation $(3)$ into equation $(2)$:

$a(10 - a) = 16$

Expand and simplify:

$10a - a^2 = 16$

Rearrange to form a quadratic equation:

$a^2 - 10a + 16 = 0$

Factor the quadratic:

$(a - 8)(a - 2) = 0$

This gives us two possible values for $a$:

$a = 2, 8$

Substitute these values back into equation $(3)$ to find the corresponding values of $b$:

$b = 10 - 2 = 8, \quad b = 10 - 8 = 2$

So, we have two possible solutions: $(a, b) = (2, 8)$ or $(a, b) = (8, 2)$.

Step 2: Calculate $a^2 - ab + b^2$ and $a^2 + ab + b^2$

Using the solutions from Step 1, we can calculate the required expressions:

Case 1: $(a, b) = (2, 8)$

$a^2 - ab + b^2 = 2^2 - 2(8) + 8^2 = 4 - 16 + 64 = \boxed{52}$

$a^2 + ab + b^2 = 2^2 + 2(8) + 8^2 = 4 + 16 + 64 = \boxed{84}$

Case 2: $(a, b) = (8, 2)$

$a^2 - ab + b^2 = 8^2 - 8(2) + 2^2 = 64 - 16 + 4 = \boxed{52}$

$a^2 + ab + b^2 = 8^2 + 8(2) + 2^2 = 64 + 16 + 4 = \boxed{84}$

As we can see, both cases yield the same results:

$a^2 - ab + b^2 = \boxed{52}$ $a^2 + ab + b^2 = \boxed{84}$

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