The number of apples of An, Binh, and Chi are the same. An gave away 17 apples, Chi gave away 19 apples, so now Chi's apples are 5 times higher than the total remaining apples of An and Binh. How many apples did each of you have at first? (Solve the above problem by equation or system of equations)

Let the initial numbers of apples is a.

An gave 17 apples

Chi gave 19 apples

So,

x - 19 = 5 (x - 17 + x)

x - 19 = 5 (2x - 17)

x - 19 = 10 x - 85

9 x = 66

x = 7

6 0

3 years ago

Thomas buys a cardboard sheet that is 8 by 12 inches. Let x be the side length of each cutout. Using complete sentences, explain

jasenka [17]

Answer: V = (12in - 2*x)*(8 in - 2*x)*x

Step-by-step explanation:

So we have a rectangular cardboard sheet, and we cut four squares of side length x in each corner so we can make a box.

Remember that for a box of length L, width W and height H, the volume is:

V = L*W*H

In this case, the length initially is 12 inches, but we remove (from each end) x inches of the length, then the length of the box will be:

L = 12 in - 2*x

For the width we have a similar case:

W = 8in - 2*x

And te height of the box will be equal to x, then:

H = x

This means that the volume is:

V = (12in - 2*x)*(8 in - 2*x)*x

Here we can see the connection between the cutout and the volume of the box

7 0

3 years ago

What is the vertex of f(x)=-x^2-8x

frez [133]

$\bf f(x) = -x^2-8x\implies f(x) = -x^2-8x+0 \\\\[-0.35em] ~\dotfill\\\\ \textit{vertex of a vertical parabola, using coefficients} \\\\ f(x)=\stackrel{\stackrel{a}{\downarrow }}{-1}x^2\stackrel{\stackrel{b}{\downarrow }}{-8}x\stackrel{\stackrel{c}{\downarrow }}{+0} \qquad \qquad \left(-\cfrac{ b}{2 a}~~~~ ,~~~~ c-\cfrac{ b^2}{4 a}\right) \\\\\\ \left(-\cfrac{-8}{2(-1)}~~,~~0-\cfrac{(-8)^2}{4(-1)} \right)\implies \left( -4~~,~~0+\cfrac{64}{4} \right)\implies (-4~,~16)$

7 0

3 years ago

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