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3 years ago

Help solve these using the addition and multiplication properties of equality

Mathematics

1 answer:

Leno4ka [110]3 years ago

7 0

#19

-4/5x=8

-4(x)/5=8

-4x/5=8

Multiply both sides by

-4x=8(5)

-4x=40

Divide both sides by -4

X= -10

#21

-4/3x+5=7

Multiply both sides by 3

-4/3x(3)+5(3)=7(3)

-4x+15=21

-4x=21-15

-4x=6

X=6/-4

X=-3/2

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Step-by-step explanation:

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The population of a small town is 39,668 and has been continuously declining at a 1.5% a year what will the population be in 13

anyanavicka [17]

Answer: 31, 932.74

Step-by-step explanation:

The population of the small town = 39,668

Yearly rate of decline = 1.5%

Therefore, to calculate 1.5% of 39,668 = 1.5 x 39,668

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100

= 595.02

So, the population is declining by 595.02 on yearly basis.

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We multiply , = 595.02 x 13

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3 years ago

Jenny washed dishes 4 times as many as her brother last month. Her brother washed dishes 8 times. Jenny said she could multiply

Julli [10]

Jenny is incorrect in her calculation.

For every time that Jenny's brother washed dishes, Jenny washed dishes 4 times. This tells that the the times they washed dishes occur in the ratio 4 :1. If Jenny's brother washed dishes 8 times, Jenny has to have washed dishes $4\times 8=32$ times. The way Jenny's is doing the calculation implies that his brother washed dishes $3*\times 8 =24$ times. He calculation yields a wrong result.

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3 years ago

If a cone with a diameter of 10 m has a surface area of 190.6m2, find its slant height. Round to the nearest tenth.

alukav5142 [94]

Answer: The slant height of the cone is 65.6 m

Step-by-step explanation:

Given: The diameter of a cone = 10 m

Surface area of cone = 190.6 m²

To find: Slant height

Diameter of cone = 10 m

Therefore Radius of cone = $\dfrac{\text {Diameter }}{2} = \dfrac{10}{2} =5m$

As we know that surface area of a cone is given by

$S.A. = \pi r(l+r)$

Where S.A. is surface area , r is the radius of cone and l is the slant height of the cone.

Let Slant height = l

So we have

$190.6 = \dfrac{22}{7} \times 5 ( 5+l)\\\\\Rightarrow 5+l= \dfrac{190.6 \times 7}{22}\\\\\Rightarrow l= \dfrac{1334.2}{22}+5\approx 60.64+5 = 65.64\approx65.6$

Hence the slant height of the cone is 65.6 m

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3 years ago