Use any method to multiply (3a + 2b – c)(a – b + 2c).

Mathematics

2 answers:

umka21 [38]3 years ago

4 0

Answer:

3a2 – 2b2 – 2c2 – ab + 5ac + 5bc

$(3a + 2b - c)(a - b + 2c) \\ = (3 {a}^{2} - 3ab + 6ac + 2ab - 2 {b}^{2} + 6bc - ac + bc - 2 {c}^{2} ) \\ = 3 {a}^{2} - ab + 5ac - 2 {b}^{2} + 5bc - {2c}^{2} \\ = 3 {a}^{2} - 2 {b}^{2} - {2c}^{2} - ab + 5ac + 5bc$

guajiro [1.7K]3 years ago

3 0

Answer:

option a is correct

Step-by-step explanation:

(3a + 2b - c)(a - b + 2c)

3a(a- b + 2c) +2b(a - b + 2c) - c(a - b + 2c)

multiply the brackets

3a^2 - 3ab + 6ac + 2ab - 2b^2 + 4bc - ac + bc - 2c^2

combine like terms

3a^2 - ab + 5ac - 2b^2 + 5bc - 2c^2

3a^2 - 2b^2 - 2c^2 - ab + 5ac + 5bc

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Use the given inverse to solve the system of equations. left brace Start 3 By 3 Matrix 1st Row 1st Column x minus y plus z 2nd C

natka813 [3]

The interpretation of the given question is as follows:

Use the given inverse to solve the system of equations

$x- y - z = -6 \\ \\ 2y + z = -6 \\ \\ 3x -8 y = - \dfrac{1}{2}$

The inverse of $\left[\begin{array}{ccc}1&-1&1\\0&2&1\\3&-8&0\end{array}\right] is \left[\begin{array}{ccc}-8&8&3\\-3&3&1\\6&-5&-2\end{array}\right]$

x =

y =

z =

Answer:

x = - 1.5

y = - 0.5

z = - 5

Step-by-step explanation:

Using the correlation of inverse of matrix AX = B to solve the question above;

AX = B

⇒ A⁻¹(AX) = A⁻¹ B

X = A⁻¹ B

So ;

X = A⁻¹ B

$\left[\begin{array}{c}x\\y\\z\end{array}\right] =$ $\left[\begin{array}{ccc}-8&8&3\\-3&3&1\\6&-5&-2\end{array}\right] =$ $\left[\begin{array}{ccc}-6\\ -6\\- \dfrac{1}{2}\end{array}\right]$

$\left[\begin{array}{c}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}(-8*-6)+(8*-6)+(3*-\dfrac{1}{2})\\(-3*-6)+(3*-6)+(1*-\dfrac{1}{2})\\(6*-6)+(5*-6)+(-2* - \dfrac{1}{2})\end{array}\right]$

$\left[\begin{array}{c}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}(48)+(-48)+(\dfrac{-3}{2})\\(18)+(-18)+(\dfrac{-1}{2})\\(-36)+(30)+(1)\end{array}\right]$