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4 years ago

Solve the equation for all values of x by completing the square. 3x^2-60x+255=0

Mathematics

1 answer:

erik [133]4 years ago

4 0

Answer:

x=5 and x=15

Step-by-step explanation:

3x^2-60x+225=0

3x^2-60x+225/3=0/3

x^2-20x+75=0

x^2-5x-15x+75=0

x(x-5)-15(x-5)=0

(x-5)(x-15)=0

x-5=0 x-15=0

x=5 x=15

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givi [52]

Answer:

Step-by-step explanation:

4 0

3 years ago

Mental math 5×395=5×(_ - _)step by step how do you solve this problem?

mr Goodwill [35]

You want to use the distributive property, i.e. the possibility to distribute a multiplication to both terms of an sum/subtraction.

In this case, if you think of 395 as of 400-5, you have

$5 \times 395 = 5 \times (400-5)$

And you can use the distributive property to write

$5 \times (400-5) = 5\times 400 - 5\times 5$

Both of these multiplications are easy to perform in your mind:

$5\times 400 - 5\times 5 = 2000 - 25 = 1975$

3 0

3 years ago

Simplify and solve for x. 5(x+20)= 7x+30

hodyreva [135]

Answer:

x = 35

Step-by-step explanation:

Solve for x:

5 (x + 20) = 7 x + 30

Expand out terms of the left hand side:

5 x + 100 = 7 x + 30

Subtract 7 x from both sides:

(5 x - 7 x) + 100 = (7 x - 7 x) + 30

5 x - 7 x = -2 x:

-2 x + 100 = (7 x - 7 x) + 30

7 x - 7 x = 0:

100 - 2 x = 30

Subtract 100 from both sides:

(100 - 100) - 2 x = 30 - 100

100 - 100 = 0:

-2 x = 30 - 100

30 - 100 = -70:

-2 x = -70

Divide both sides of -2 x = -70 by -2:

(-2 x)/(-2) = (-70)/(-2)

(-2)/(-2) = 1:

x = (-70)/(-2)

The gcd of -70 and -2 is -2, so (-70)/(-2) = (-2×35)/(-2×1) = (-2)/(-2)×35 = 35:

Answer: x = 35

6 0

4 years ago

Read 2 more answers

Calculate the value of x if 2x/3=8/5

Cloud [144]

Answer:

12/5 or 2⅖

Step-by-step explanation:

2x/3 = 8/5

2x = 3 × 8/5

2x = 24/5

x = 24/5 ÷ 2

x = 12/5

Or 2⅖

5 0

3 years ago

so this boy liked me for years in middle school and i think he finally got over me once i didn't really show much interest in hi

sasho [114]

Ah, female problems, Amiright?

If you don't feel comfortable talking to him, then you don't have to, it's not against the law. And if he tries talking to you and it becomes awkward, make sure that someone is with you that you know will keep a good convo going.

Also, he probably liked you because of your personality, or maybe the way you look, or talk, or wear you hair, or even your style. The possiblys are endless.

Honestly, I've been in a similar situation before, that's how I know what to do.

6 0

3 years ago