How do I solve this system of equations by adding, subtracting, or multiplying? x-y=8;x+y=12

1 answer:

Natasha2012 [34]3 years ago

7 0

By substitution.
Get y or x alone then insert it into the other equation solving for one of the two variables. After that substitute ur answer into one of the equations then solve.

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Dominik [7]

Answer:

Step-by-step explanation:

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7 0

3 years ago

How do I solve and graph this

White raven [17]

I hope this helps you out

5 0

4 years ago

Find the missing coefficients y=ax^2-10x+c vertex :(-5,20)

Citrus2011 [14]

Remember, for $y=ax^2+bx+c$ the x value of the vertex is $\frac{-b}{2a}$

so
given
x value of vertex is -5
and
$y=ax^2-10x+c$
$\frac{-b}{2a}=\frac{-(-10)}{2a}=\frac{10}{2a}=$
$\frac{5}{a}=-5$
multiply both sides by a
5=-5a
divvide both sides by -5
-1=a
a=-1

$y=-1x^2-10x+c$
comlete the square
remember if we do
$y=a(x-h)^2+k$ (h,k) is the vertex
I know, we can subsitute the known values of te vertex
-5 for h and 20 for k then expand

$y=-1(x-(-5))^2+20$
$y=-1(x+5)^2+20$
$y=-1(x^2+10x+25)+20$
$y=-1x^2-10x-25+20$
$y=-1x^2-10x-5$

a=-1
c=-5

5 0

3 years ago

Can someone help me please!!! Thank you

Semmy [17]

Steps of construction:

1. Draw a circle with centre B.

2. Draw a circle with centre C.

3. Both circles intersect each other at a point D

4. Join A and D.

5. So, AD bisects angle CAB.

A rough figure is shown in the picture.