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3 years ago

15

X and y is the variable 4x-7y=3 x-7y=-15 what is the answer please

1 answer:

andrezito [222]3 years ago

6 0

Use linear combination to solve this. It is much faster than substitution. I would start by multiplying the bottom equation by -1.
<span>4x-7y=3
-x+7y=15</span>
Then, add the two equations together. The result is:
3x=18.
You've eliminated one variable. Now you can solve for the other one.
Divide both sides by 3 to get
x=6
Plug this into one of the original equations, then solve for y
-(6)+7y=15
7y=21
y=3

Check your work by plugging these values into both equations to see if they remain true

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Step-by-step explanation:

Given

$h(t) = -16t^2 + 7t + 63$

Solving (a): Equation when it hits the ground.

This means that $h(t) = 0$

So, we have:

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Solving (b): The value of t in (a)

$-16t^2 + 7t + 63=0$

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This gives:

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$t = \frac{-7 \± 63.88}{-32}$

Split

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