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3 years ago

Solve by substitution 3x - 5y = -1 , x-y = -1

Mathematics

1 answer:

nevsk [136]3 years ago

6 0

Answer:

(-2, -1)

Step-by-step explanation:

first you must reorganize the equations so that one of them has x or y equaling to something

x - y = -1 --> x = y - 1

then substitute that in for x

3(y - 1) - 5y = -1

and solve for y

3y - 3 - 5y = -1

-2y = 2

y is -1

then plug it back in to an equation to find x

x + 1 = -1

x is -2

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Determine the value of k if 12x2 + kx/ 4x= 3x – 5.

Oxana [17]

Answer:

k = -20.

Step-by-step explanation:

Do the division:

4x ) 12x^2 + kx ( 3x

12x^2 + k/4

So k/4 = - 5

k = -20.

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3 years ago

A building that is 750 feet tall casts a shadow the is 111 feet long. find the angle of of elevation, in degrees, to the sun.

stepan [7]

Imagine the shadow and the building height forms a right angle triangle;

We know the height and the shadow make up the "legs" of the triangle,

a²+b²=c²
(750)²+(111)²=c²
562500+12321=c²
574821=c²
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Hope I helped :)

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3 years ago

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Kitty [74]

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3 years ago

The height h (in feet) of an object t seconds after it is dropped can be modeled by the quadratic equation h = -16t2 + h0, where

lawyer [7]

$\bf h=-16t^2+255\implies h=-16t^2+0t+255
\\\\\\
~~~~~~~~~~~~\textit{quadratic formula}\\\\
\begin{array}{lcccl}
h=& -16 t^2& +0 t& +255\\
&\uparrow &\uparrow &\uparrow \\
&a&b&c
\end{array} 
\qquad \qquad 
h= \cfrac{ - b \pm \sqrt { b^2 -4 a c}}{2 a}
\\\\\\
h=\cfrac{-0\pm\sqrt{0^2-4(-16)(255)}}{2(-16)}\implies h=\cfrac{\pm\sqrt{16320}}{-32}
\\\\\\
h=\cfrac{\pm\sqrt{8^2\cdot 255}}{-32}\implies h=\cfrac{\pm 8\sqrt{255}}{-32}\implies h=\cfrac{\mp \sqrt{255}}{4}
\\\\\\
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5 0

3 years ago

Read 2 more answers

Jennie bought six boxes of pencils for four dollars. How many boxes of pencils can she buy for six dollars?

kap26 [50]

Answer:

9 boxes.

Step-by-step explanation:

6 boxes cost 4 dollars

Therefore 1 box costs 4/6 = 2/3 dollar.

So for 6 dollars you can buy 6 / 2/3

= 6*3/2

= 9 boxes.

3 0

3 years ago