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4 years ago

Year 9 Maths - linear equations please help

Mathematics

2 answers:

MAXImum [283]4 years ago

6 0

X=3, Y=9
X+Y=12
Y=X+6

X+X+6=12
2X=6
X=3

Y=3+6=9

jek_recluse [69]4 years ago

3 0

Answer:

x=1 & y=6 or (1,6)

Step-by-step explanation:

3x-x+5=7 Substitute the 2nd equation in for y

2x+5=7 Do 3x-x to get 2x

2x=2 Subtract 5 from both sides

x=1 Divide 2 from both sides

y=1+5 Insert 1 as x

y=6 Add 1+5 to solve for y

Hope this helped!

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Are these two ratios proportional?<br><br> 2/5 and 3/4<br><br> Yes or no?

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3 years ago

Point G is the centroid of the right △ABC with hypotenuse AB=18 in. Find CG.

natita [175]

<h3>Answer:</h3>

6 in

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5 0

4 years ago

Read 2 more answers

-x=-y+2 and 3y+4=2x solve using matrices

MissTica

$\begin{cases}-x=-y+2\\3y+4=2x\end{cases}\implies\begin{cases}x-y=-2\\2x-3y=4\end{cases}$

In matrix form, this is

$\begin{bmatrix}1&-1\\2&-3\end{bmatrix}\begin{bmatrix}x\\y\end{bmatrix}=\begin{bmatrix}-2\\4\end{bmatrix}$

The coefficient matrix has determinant

$\begin{vmatrix}1&-1\\2&-3\end{vmatrix}=-3+2=-1\neq0$

so it has an inverse, which is

$\begin{bmatrix}1&-1\\2&-3\end{bmatrix}^{-1}=\begin{bmatrix}3&-1\\2&-1\end{bmatrix}$

Multiply both sides by the inverse matrix:

$\begin{bmatrix}3&-1\\2&-1\end{bmatrix}\begin{bmatrix}1&-1\\2&-3\end{bmatrix}\begin{bmatrix}x\\y\end{bmatrix}=\begin{bmatrix}3&-1\\2&-1\end{bmatrix}\begin{bmatrix}-2\\4\end{bmatrix}$

$\implies\begin{bmatrix}x\\y\end{bmatrix}=\begin{bmatrix}-10\\-8\end{bmatrix}$

so that $x=-10$ and $y=-8$ .

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4 years ago

Anastasia’s mom baked a giant sugar cookie for her birthday. On her birthday, ⅝ of the birthday cookie was eaten. The next day h

devlian [24]

Answer:

9/32 of the cookie was left for Stephanie to eat after lunch

Step-by-step explanation:

Anastasia’s mom baked a giant sugar cookie for her birthday.

On her birthday, ⅝ of the birthday cookie was eaten.

So, remaining cake = $1 - \frac{5}{8}=\frac{3}{8}$

The next day her brother ate ¼ of what remained.

Amount of cake eaten by her brother = $\frac{1}{4}(\frac{3}{8})=\frac{3}{32}$

So, remaining cake = $\frac{3}{8}-\frac{3}{32}=\frac{12-3}{32}=\frac{9}{32}$

Hence 9/32 of the cookie was left for Stephanie to eat after lunch

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3 years ago

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Mrrafil [7]

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3 years ago

Read 2 more answers