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tamaranim1 [39]

3 years ago

5

Solve the matrix equation. The inverse of the coefficient matrix is given. EXPLAIN. The answer's D. (2/9,-4/3,-1/3)

1 answer:

Lerok [7]3 years ago

4 0

Answer:

Right answer is D number

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Will give brainliest answer!

kifflom [539]

5x + 60y = 35

x +y = 1.5 : rewrite as x = 1.5-y and substitute this formula for x in the first one:

5(1.5-y) + 60y = 35

distribute:

7.5 - 5y + 60y = 35

combine like terms:

7.5 + 55y = 35

subtract 7.5 from both sides:

55y = 27.5

divide both sides by 55 to solve for y

y = 27.5 / 55 = 0.5

now substiute 0.5 for y in the 2nd equation:

x + 0.5 = 1.5

x = 1.5 - 0.5 = 1

he walked for 1 hour

8 0

3 years ago

2. Carl needs 15 hours longer than Jennifer to paint a room. If they work together, they can complete the job in 4 hours. Explai

nasty-shy [4]

Answer:

Jennifer would complete the job on her own in 5 hours.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}$

$\Delta = b^{2} - 4ac$

Rates

The together rate is the sum of their separates rate.

We have that:

Jennifer takes x hours to complete the job on her own, so her rate is 1/x.

Carl needs 15 hours longer than Jennifer, that is, 15 + x hours, so his rate is 1/(15+x).

The together rate is 1/4. So

$\frac{1}{4} = \frac{1}{x} + \frac{1}{15+x}$

$\frac{1}{4} = \frac{15 + x + x}{x(15+x)}$

$\frac{1}{4} = \frac{15 + 2x}{x(15+x)}$

Applying cross multiplication.

$x^2 + 15x = 4(15 + 2x)$

$x^2 + 15x = 60 + 8x$

$x^2 + 7x - 60 = 0$

Quadratic equation with $a = 1, b = 7, c = -60$ . So

$\Delta = 7^{2} - 4*1*60 = 289$

$x_{1} = \frac{-7 + \sqrt{289}}{2} = 5$

$x_{2} = \frac{-7 - \sqrt{289}}{2} = -12$

Since the time to complete the job has to be a positive value.

Jennifer would complete the job on her own in 5 hours.

4 0

3 years ago

there were 50 cars parked at the airport car rental lot. Of those 50 cars, 10% were red. How many cars were red?

solmaris [256]

10% of the 50 were red.

10% * 50

(10/100) * 50

(1/10) * 50

= 5

5 were red.

8 0

3 years ago

Read 2 more answers

Click on the point that best represents the location of −√5 on the number line.

navik [9.2K]

Answer:

The dot all the way on the left. The one between 2 and 3 I believe.

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Work on Screenshot i got this one wrong when i first tried it

adell [148]

The answer to your question is 30

3 0

3 years ago