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3 years ago

HELP ASAP PLEASE!!!

Mathematics

1 answer:

grigory [225]3 years ago

7 0

The quadratic fomula:

$ax^2+bx+c=0\\\\\Delta=b^2-4ac\\\\If\ \Delta0,\ then\ \boxed{TWO\ SOLUTIONS:\ x_1=\dfrac{-b-\sqrt\Delta}{2a}\ and\ x_2=\dfrac{-b+\sqrt\Delta}{2a}}-----------------------------------------------$

We have the equation:

$2x^2-7x-21=0\\\\a=2,\ b=-7,\ c=-21\\\\\Delta=(-7)^2-4(2)(-21)=49+168=217 > 0\\\\x_1=\dfrac{-(-7)-\sqrt{217}}{2(2)}=\dfrac{7-\sqrt{217}}{4}\approx-1.93\\\\x_2=\dfrac{-(-7)+\sqrt{217}}{(2)(2)}=\dfrac{7+\sqrt{217}}{4}\approx5.43\\\\Answer:\ \boxed{\boxed{2.\ -1.93\ and\ 5.43}}$

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If i walk 4 miles per hour how long will it take to walk a mile

fiasKO [112]

Hi there! The answer is 15 minutes.

Walking 4 miles per hour means that it takes you 60 minutes to walk 4 miles. To find the time it takes you to walk 1 mile, we must divide both sides by 4.

4 miles equals 60 minutes.
1 mile equals 60 / 4 = 15 minutes.

The answer is 15 minutes.

4 0

3 years ago

Its super duper easy but im having some trouble so can someone help me?

Klio2033 [76]

together = add

add the fractions

3 7/10 + 5 9/10

add the whole numbers first

3+5=8

add the fractions

7/10+9/10= 16/10

8 16/10

reduce 16/10 divide by 2

16/2= 8

10/2= 5

8 8/5

whole number changes to 9

8-5=3

denominator stays the same

9 3/5

Answer:

9 3/5

8 0

3 years ago

Sandra's scores on the first 4 tests were 87%, 92%, 76%,and 89%. What is the minimum score she needs to make on the fifth test s

sergejj [24]

Answer:

Sandra need to score at least 56% in her fifth test so that her average is 80%.

Step-by-step explanation:

Given:

First 4 test scores = 87%, 92%, 76%,89%

Average targeted = 80%

We need to find the minimum score she needs to make on fifth test to achieve average of at least 80%.

Solution:

Let the minimum score she needs to make in fifth test be 'x'.

Total number of test = 5

Now we know that;

Average is equal to sum of all the scores in the test divided by number of test.

framing in equation form we get;

$\frac{87+92+76+89+x}{5}=80$

Multiplying both side by 5 we get;

$\frac{344+x}{5}\times 5=80\times 5\\\\344+x=400$

Subtracting both side by 344 we get;

$344+x-344=400-344\\\\x=56\%$

Hence Sandra need to score at least 56% in her fifth test so that her average is 80%.

5 0

3 years ago

Please help Please also explain

schepotkina [342]

Answer: it is equal

Step-by-step explanation: you subtract 15-4 which equals 11. the exponent is the only thing being subtracted since it's a fraction. therefore it equals 10(11)

3 0

3 years ago

What Is The Answer .?

mamaluj [8]

$p + 9 = 25$

7 0

3 years ago