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3 years ago

Help me with this asap right now please i will mark brainlest

Mathematics

1 answer:

Rainbow [258]3 years ago

4 0

Answer:

5(8x+6y) & 10(4x+3y) & 2(20x+15y)

Step-by-step explanation:

the first doesn't include y, the third is too large, the fifth has y in the multiplier.

the only left are the fourth and second and sixth.

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Let a, b, c, and d be nonzero real numbers. If the quadratic equation ax (cx + d) = –b (cx + d) is solved for x, which of the fo

gayaneshka [121]

Answer:

$x_1=-\frac{b}a,x_2=-\frac{d}c$

Step-by-step explanation:

Solving for x:

$ax(cx + d) =-b(cx +d)\\ax(cx + d)+b(cx+d)=0\\(ax+b)(cx+d)=0$

In this form is easy to identify the factors of the quadratic function: $(ax+b)(cx+d)$ . The two solutions are the values that make each of the factors equals to zero.

$ax_1+b=0\\ax_1=-b\\x_1=-\frac{b}a\\cx_2+d=0\\cx_2=-d\\x_2=-\frac{d}c$

7 0

4 years ago

For the quadratic equation 3x^2-18x-21=0, x1 and x2 are the roots. Find:

givi [52]

(x_1+x_2)=-b/a=18/3=6

x_1x_2=c/a=-21/3=-7

(x_1+x_2)²-2x_1x_2=x_1^2+x2²
x1²+x2²=(6)²-2(-7)=36+14=50

(x_1-x_2)²

x1²+x2²-2x_1x2
50+14
64

x_1-x_2=8

3 0

3 years ago

Read 2 more answers

If 5/6 is divided by a certain fraction a/b, the result is 1/4. What is the fraction a/b?

vodka [1.7K]

The fraction would be 10/3. Hope this helps!

3 0

3 years ago

Betsy, a recent retiree, requires 5,000 per year in extra income. She has $70,000 to invest and can invest in B rated bonds payi

Kisachek [45]

B = amount invested in B bonds

c = amount invested in CDs

so.. she's got $70000 burning a hole in her pocket and she wants to invest them to get a yield of 5000 in interest from both of them.

we know that, whatever "c" and "b" are, we know that b + c = 70,000.

how much is 13% of b? well, (13/100) * b, or 0.13b
how much is 5% of c? well, (5/100) * a, or 0.05c

we know that, the yield or interest earned from them, must be 5000, thus 0.13b + 0.05c = 5000.

$\bf \begin{cases}
b+c=7000\implies \boxed{c}=70000-b\\
0.13b+0.05c=5000\\
----------\\
0.13b+0.05\left( \boxed{70000-b} \right)=5000
\end{cases}
\\\\\\
0.13b-0.05b+3500=5000\implies 0.08b=1500\implies b=\cfrac{1500}{0.8}
\\\\\\
b=18750$

how much did she invest in CDs? well, c = 70000 - b.

5 0

3 years ago

Consider that the length of rectangle A is 21 cm and its width is 7 cm. Which rectangle is similar to rectangle A?

Greeley [361]

Question is incomplete, complete question is given below.

Consider that the length of rectangle A is 21 cm and its width is 7 cm. Which rectangle is similar to rectangle A? A) A rectangle with a length of 9 cm and a width of 3 cm. B) A rectangle with a length of 20 cm and a width of 10 cm. C) A rectangle with a length of 18 cm and a width of 9 cm. D) A rectangle with a length of 27 cm and a width of 3 cm.

Answer:

A) A rectangle with a length of 9 cm and a width of 3 cm.

Step-by-step explanation:

Given,

Length = 21 cm Width = 7 cm

$Ratio = \frac{Length}{Width}\\\\Ratio = \frac{21}{7}=3:1$

For the similarity of rectangle the ratio of length to width of any two rectangles should be equal.

So we have four options given;

A) A rectangle with a length of 9 cm and a width of 3 cm.

$Ratio =\frac{9}{3}=3:1$

Here the ratio is equal as of rectangle A. So this rectangle is similar to rectangle A.

B) A rectangle with a length of 20 cm and a width of 10 cm.

$Ratio =\frac{20}{10}=2:1$

Here the ratio is not equal as of rectangle A. So this rectangle is not similar to rectangle A.

C) A rectangle with a length of 18 cm and a width of 9 cm.

$Ratio =\frac{18}{9}=2:1$

Here the ratio is not equal as of rectangle A. So this rectangle is not similar to rectangle A.

D) A rectangle with a length of 27 cm and a width of 3 cm.

$Ratio =\frac{27}{3}=9:1$

Here the ratio is not equal as of rectangle A. So this rectangle is not similar to rectangle A.

Thus the correct option is A) A rectangle with a length of 9 cm and a width of 3 cm.

4 0

4 years ago