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3 years ago

Helppppp I need help I will make u a brainlist

Mathematics

1 answer:

nadezda [96]3 years ago

5 0

Answer:

answer is D

Step-by-step explanation:

pretty simple

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Help me please , will mark brainliest

NISA [10]

Answer:

Step-by-step explanation:

diameter is half of radius

7 0

3 years ago

Brass is made up of copper and zinc. 100 grams of brass contains 20 grams of zinc.

Nana76 [90]

Answer:

A. 12 grams Zn

B. 280 g of copper.

Step-by-step explanation:

100 grams of brass

20 grams of zinc

100 grams of brass has 20 grams of Zn.

20/100 = 0.200 Zn 20% Zn and 80% copper.

A. (60 g brass)*(0.2) = 12 grams Zn

B. (350 g brass)*(0.80) = 280 g of copper.

5 0

2 years ago

Show work please \sqrt(x+12)-\sqrt(2x+1)=1

Nesterboy [21]

Answer:

$x=4$

Step-by-step explanation:

Given $\displaystyle\\\sqrt{x+12}-\sqrt{2x+1}=1$ , start by squaring both sides to work towards isolating $x$ :

$\displaystyle\\\left(\sqrt{x+12}-\sqrt{2x+1}\right)^2=\left(1\right)^2$

Recall $(a-b)^2=a^2-2ab+b^2$ and $\sqrt{a}\cdot \sqrt{b}=\sqrt{a\cdot b}$ :

$\displaystyle\\\left(\sqrt{x+12}-\sqrt{2x+1}\right)^2=\left(1\right)^2\\\implies x+12-2\sqrt{(x+12)(2x+1)}+2x+1=1$

Isolate the radical:

$\displaystyle\\x+12-2\sqrt{(x+12)(2x+1)}+2x+1=1\\\implies -2\sqrt{(x+12)(2x+1)}=-3x-12\\\implies \sqrt{(x+12)(2x+1)}=\frac{-3x-12}{-2}$

Square both sides:

$\displaystyle\\(x+12)(2x+1)=\left(\frac{-3x-12}{-2}\right)^2$

Expand using FOIL and $(a+b)^2=a^2+2ab+b^2$ :

$\displaystyle\\2x^2+25x+12=\frac{9}{4}x^2+18x+36$

Move everything to one side to get a quadratic:

$\displaystyle-\frac{1}{4}x^2+7x-24=0$

Solving using the quadratic formula:

A quadratic in $ax^2+bx+c$ has real solutions $\displaystyle x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ . In $\displaystyle-\frac{1}{4}x^2+7x-24$ , assign values:

$\displaystyle \\a=-\frac{1}{4}\\b=7\\c=-24$

Solving yields:

$\displaystyle\\x=\frac{-7\pm \sqrt{7^2-4\left(-\frac{1}{4}\right)\left(-24\right)}}{2\left(-\frac{1}{4}\right)}\\\\x=\frac{-7\pm \sqrt{25}}{-\frac{1}{2}}\\\\\begin{cases}x=\frac{-7+5}{-0.5}=\frac{-2}{-0.5}=\boxed{4}\\x=\frac{-7-5}{-0.5}=\frac{-12}{-0.5}=24 \:(\text{Extraneous})\end{cases}$

Only $x=4$ works when plugged in the original equation. Therefore, $x=24$ is extraneous and the only solution is $\boxed{x=4}$

4 0

2 years ago

Is the product of 2 perfect squares always a perfect square?

nexus9112 [7]

The product of two perfect squares is a perfect square.

Proof of Existence:
Suppose a = 2^2 , b = 3^2 [ We have to show that the product of a and b is a perfect square.] then
c^2 = (a^2) (b^2)
= (2^2) (3^2)
= (4)9
= 36
and 36 is a perfect square of 6. This is to be shown and this completes the proof

3 0

3 years ago

Select the expression that can be used to find the price of a $350 telescope after a 48% markup.

zvonat [6]

Answer:

Step-by-step explanation:

you have to turn the48 to a decimal

4 0

2 years ago