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2 years ago

What is the first step in the solution of 3x2+6x=12 by completing the square?

Mathematics

2 answers:

KiRa [710]2 years ago

8 0

3x²+6x=12

Divide all terms by a i.e 3

We get

x²+2x=4

r²+2r=4

Option B is correct

aleksandrvk [35]2 years ago

7 0

Answer:

B: r² + 2r = 4

Explanation:

$\rightarrow \sf 3x^2+6x=12$

divide both sides by 3

$\rightarrow \sf x^2+2x=4$ ← This is the result of the first step.

factor out the common term

$\rightarrow \sf x(x+2) = 4$

set to 0

$\rightarrow \sf x = 4, \ x+2 = 4$

simplify

$\rightarrow \sf x = 4, \ x= 2$

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A school has 400 students. They all come to school by bus, and each bus carries the same number of students. How many students m

Ainat [17]

Depends. All multiples of 400, you could have many different options. For example, 400 buses 1 kid on ea. 40 buses 10 kids on ea.

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8 0

2 years ago

Read 2 more answers

Two corresponding sides of similar triangles are 2 cm and 5 cm. What is the area of the second triangle if the area of the first

Stella [2.4K]

Answer:

(1) Area of second triangle= 50 cm^2.

(2) Area of ΔABC=98 cm^2.

and Area of ΔDFG=175 cm^2.

Step-by-step explanation:

" For two similar triangles the ratio of sides is equal to the ratio of square of their areas".

i.e. if a,b are the corresponding sides of two similar triangles and let A and B denote the area of two triangles then we have the relation as:

$\dfrac{a^2}{b^2}=\dfrac{A}{B}$

(1)

for the first question:

we have a=2, b=5.

A=8 cm^2.

Hence,

$\dfrac{2^2}{5^2}=\dfrac{8}{B}\\\\\dfrac{4}{25}=\dfrac{8}{B}$

B=50 cm^2.

Hence, the area of second triangle is 50 cm^2.

(2)

In second option we have:

a=6 and b=5.

A-B=77 cm^2.

A=77+B

$\dfrac{6^2}{5^2}=\dfrac{A}{B}\\ \\\dfrac{36}{25}=\dfrac{77+B}{B}\\ \\36B=25\times77+25B\\\\36B-25B=25\times77\\\\11B=25\times77\\\\B=25\times7\\\\B=175$