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3 years ago

the width of a rectangle is 7 cm less than twice its length. its area is 30 square cm. find the dimensions

Mathematics

1 answer:

spayn [35]3 years ago

5 0

Answer:

l = 6 cm

w = 5 cm

Step-by-step explanation:

l(2l - 7) = 30

2l^2 - 7l - 30

(2l + 5)(l - 6)

l = 6

2(6) - 7 = 5

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80 POINTS for right answer! 4 questions! Math only

34kurt

1.
A graph of linear function is a straight line.
Linear function in a slope-intercept form: y = mx + b

Answer: Equation 3: y = 12x + 17.

2.
x|-1 | 0 | 1 | ? |
y| 4 | 7 |10| ? |

a slope: $m=\dfrac{y_2-y_1}{x_2-x_1}$

We choose:
$(-1; 4)\to x_1=-1\ and\ y_1=4\\(0;\ 7)\to x_2=0\ and\ y_2=7$

subtitute:

$m=\dfrac{7-4}{0-(-1)}=\dfrac{3}{1}=3$

a slope-intercept form: $y-y_1=m(x-x_1)$

subtitute:

$y-4=3(x-(-1))\\\\y-4=3(x+1)\\\\y-4=3x+3\ \ \ \ |add\ 4\ to\ both\ sides\\\\y=3x+7\ (*)$

subtitute x = 2 to the equation (*):

$y=3\cdot2+7=6+7=13$

Answer: (2, 13)

3.
(-2; 7), (-5; 4)

the slope: $m=\dfrac{4-7}{-5-(-2)}=\dfrac{-3}{-5+2}=\dfrac{-3}{-3}=1$

$y-7=1(x-(-2))\to y-7=x+2\ \ \ \ |add\ 7\ to\ both\ sides\\y=x+9$

check other:

$(-8;\ 1)\to L=1;\ R=-8+9=1;\ L=R-correct\\(-11;-2)\to L=-2;\ R=-11+9=-2;\ L=R-correct$

The conclusion: It's a linear function

Answer: It is a linear function because there is a constant rate of change in both the input and output values.

4.
y = 3x + 5 /look at the picture/

Answer: It is a linear function because its graph contains the points (0, 5), (1, 8), (2, 11), which are on a straight line.

check:
$(0; 5)\to L=5; R=3\cdot0+5=5;\ L=R-correct\\(1;\ 8)\to L=8;\ R=3\cdot1+5=8;\ L=R-correct\\(2;\ 11)\to L=11;\ R=3\cdot2+5=11;\ L=R-correct$

8 0

3 years ago

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What is the volume of a sphere with a radius of 9 inches?

OLga [1]

Volume of a sphere: (4/3)πr³
r=radius=9 in

Volume=(4/3)*π*(9 in)³=972π cubic inches≈3053.63 in³

answer: D) 972π cubic inches (3053.63 in³ is correct)

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3 years ago

Amy buys 8 sandwiches and 12 waters.her total cost is 8s+12 how much did she pay. S=sandwiches

Mrac [35]

Answer:

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Step-by-step explanation:

im not sure kung minus o plus kasi kung kinus mababa lang binayad nya

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2x^2=3x+10 completing the square

galina1969 [7]

Answer:

$x_{1} = \frac{ - \sqrt{89 + 3} }{4}$

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Step-by-step explanation:

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yuradex [85]

Answer:

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