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3 years ago

14

John mows 6 lawns a week and makes 90 dollars. If he made 270 dollars how many lawns did he mow??? Please help im really struggl

ing???

1 answer:

tangare [24]3 years ago

7 0

Answer:

Step-by-step explanation:

90 × 3=270 dollars

6×3= 18 lawns

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A rectangle with an area of 4/7 m2 is dilated by a factor of 7. What is the area of the dilated rectangle

tatyana61 [14]

according to the picture we have:

x.y=4.7

(7)x(7)y=49xy=(49)(4.7)=230.3

6 0

3 years ago

Solve The Equation <br> 4x×9y=7<br> 4x-9y=9

hoa [83]

Answer:

$\large\boxed{x=\dfrac{9}{8}-\dfrac{\sqrt{109}}{8},\ y=-\dfrac{1}{2}-\dfrac{\sqrt{109}}{18}}\\or\\\boxed{x=\dfrac{9}{8}+\dfrac{\sqrt{109}}{2},\ y=-\dfrac{1}{2}+\dfrac{\sqrt{109}}{18}}$

Step-by-step explanation:

$\left\{\begin{array}{ccc}4x\times9y=7&(1)\\4x-9y=9&(2)\end{array}\right\\\\(2)\\4x-9y=9\qquad\text{subtract}\ 4x\ \text{from both sides}\\-9y=-4x+9\qquad\text{change the signs}\\9y=4x-9\qquad\text{substitute it to (1)}\\\\4x(4x-9)=7\qquad\text{use the distributive property}\ a(b+c)=ab+ac\\(4x)(4x)+(4x)(-9)=7\\(4x)^2-36x=7\\(4x)^2-2(4x)(4.5)=7\qquad\text{add}\ 4.5^2\ \text{to both sides}\\(4x)^2-2(4x)(4.5)+4.5^2=7+4.5^2\qquad\text{use}\ (a-b)^2=a^2-2ab+b^2$

$(4x-4.5)^2=7+20.25\\(4x-4.5)=27.25\to 4x-4.5=\pm\sqrt{27.25}\\\\4x-\dfrac{45}{10}=\pm\sqrt{\dfrac{2725}{100}}\\\\4x-\dfrac{45}{10}=\pm\dfrac{\sqrt{2725}}{\sqrt{100}}\\\\4x-\dfrac{45}{10}=\pm\dfrac{\sqrt{25\cdot109}}{10}\\\\4x-\dfrac{45}{10}=\pm\dfrac{\sqrt{25}\cdot\sqrt{109}}{10}\\\\4x-\dfrac{45}{10}=\pm\dfrac{5\sqrt{109}}{10}\qquad\text{add}\ \dfrac{45}{10}\ \text{to both sides}\\\\4x=\dfrac{45}{10}\pm\dfrac{5\sqrt{109}}{10}$

$4x=\dfrac{9}{2}\pm\dfrac{\sqrt{109}}{2}\qquad\text{divide both sides by 4}\\\\x=\dfrac{9}{8}\pm\dfrac{\sqrt{109}}{8}\\\\\text{Put the values of}\ x\ \text{to (2):}\\\\9y=4\left(\dfrac{9}{8}\pm\dfrac{\sqrt{109}}{8}\right)-9\\\\9y=\dfrac{9}{2}\pm\dfrac{\sqrt{109}}{2}-\dfrac{18}{2}\\\\9y=-\dfrac{9}{2}\pm\dfrac{\sqrt{109}}{2}\qquad\text{divide both sides by 9}\\\\y=-\dfrac{1}{2}\pm\dfrac{\sqrt{109}}{18}$

8 0

3 years ago

What is the value of x? x+15=2x-40

IrinaVladis [17]

Answer:

55 =x

Step-by-step explanation:

x+15=2x-40

Subtract x from each side

x-x+15=2x-x-40

15 = x-40

Add 40 to each side

15+40 = x-40+40

55 =x

7 0

2 years ago

Read 2 more answers

The frequency of the musical note c4 is about 126.63 hz

daser333 [38]

Answer:

Each octave change requires a doubling of the frequency.

Therefore, one octave above 126.63 is 126.63 * 2 which equals

253.26

Step-by-step explanation:

5 0

3 years ago

A machine that produces ball bearings has initially been set so that the true average diameter of the bearings it produces is .5

Elodia [21]

Answer:

7.3% percentage of the bearings produced will not be acceptable.

Step-by-step explanation:

Consider the provided information.

Average diameter of the bearings it produces is .500 inches. A bearing is acceptable if its diameter is within .004 inches of this target value.

Let X is the normal random variable which represents the diameter of bearing.

Thus, 0.500-0.004<X<0.500+0.004

0.496<X<0.504

The bearings have normally distributed diameters with mean value .499 inches and standard deviation .002 inches.

Use the Z score formula: $\frac{X-\mu}{\sigma}$

Therefore

$\frac{0.496-0.499}{0.002}\leq z\leq \frac{0.504-0.499}{0.002}$

$\frac{-0.003}{0.002}\leq z\leq \frac{0.005}{0.002}$

$-1.5\leq z\leq 2.5$

Now use the standard normal table and determine the probability of that a ball bearing will be acceptable.

$P(-1.5\leq z\leq 2.5)=0.9938-0.0668=0.9270$

We need to find the percentage of the bearings produced will not be acceptable.

So subtract it from 1 as shown.

1-0.9270=0.073

Hence, 7.3% percentage of the bearings produced will not be acceptable.

3 0

3 years ago