All categories

3 years ago

Simplify (7x-1)(2x+5)

2 answers:

6 0

$\text{Simplify by using FOIL}\\\\\text{(First, Outside, Inside, Last}\\\\\text{Solve:}\\\\(7x-1)(2x+5)\\\\(7x)(2x)+(7x)(5)+(-1)(2x)+(-1)(5)\\\\14x^2+35x-2x-5\\\\\text{Combine like terms}\\\\\boxed{14x^2+33x-5}$

Alex73 [517]3 years ago

5 0

Step-by-step explanation:

$(7x-1)(2x+5) = 0 \\ 14x {}^{2} + 35x - 2x - 5 = 0 \\ 14x {}^{2} + 33x - 5 = 0 \\$

now,

$14 {x}^{2} - 2x + 35x - 5 = 0 \\ 2x(7x - 1) + 5(7x - 1) = 0 \\ (2x + 5)(7x - 1) = 0 \\ 2x + 5 = 0 \: \: \: \: or \: \: \: \: \: 7x - 1 = 0 \\ \\ x = - \frac{5}{2} \: \: \: \: or \: \: \: \: x = \frac{1}{7}$

You might be interested in

Find the distance d(A,B) between points A and B.

Misha Larkins [42]

Answer:

A(4,-5) ; B(4,3)

distance d(A,B) = $\sqrt{( 4 - 4)^{2} + (3 -(-5))^{2} }$ = 8

7 0

3 years ago

HELP FAST DUE IN 10 minutes WILL MARK BRAINLIEST SOMEONE PLEASE HELP

WARRIOR [948]

Answer:

your answer is correct -7,-2

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Solve these linear equations in the form y=yn+yp with yn=y(0)e^at.

WINSTONCH [101]

Answer:

a) $y(t) = y_{0}e^{4t} + 2$ . It does not have a steady state

b) $y(t) = y_{0}e^{-4t} + 2$ . It has a steady state.

Step-by-step explanation:

a) $y' -4y = -8$

The first step is finding $y_{n}(t)$ . So:

$y' - 4y = 0$

We have to find the eigenvalues of this differential equation, which are the roots of this equation:

$r - 4 = 0$

$r = 4$

So:

$y_{n}(t) = y_{0}e^{4t}$

Since this differential equation has a positive eigenvalue, it does not have a steady state.

Now as for the particular solution.

Since the differential equation is equaled to a constant, the particular solution is going to have the following format:

$y_{p}(t) = C$

$(y_{p})' -4(y_{p}) = -8$

$(C)' - 4C = -8$

C is a constant, so (C)' = 0.

$-4C = -8$

$4C = 8$

$C = 2$

The solution in the form is

$y(t) = y_{n}(t) + y_{p}(t)$

$y(t) = y_{0}e^{4t} + 2$

b) $y' +4y = 8$

The first step is finding $y_{n}(t)$ . So:

$y' + 4y = 0$

We have to find the eigenvalues of this differential equation, which are the roots of this equation:

$r + 4 =$

$r = -4$

So:

$y_{n}(t) = y_{0}e^{-4t}$

Since this differential equation does not have a positive eigenvalue, it has a steady state.

Now as for the particular solution.

Since the differential equation is equaled to a constant, the particular solution is going to have the following format:

$y_{p}(t) = C$

$(y_{p})' +4(y_{p}) = 8$

$(C)' + 4C = 8$

C is a constant, so (C)' = 0.

$4C = 8$

$C = 2$

The solution in the form is

$y(t) = y_{n}(t) + y_{p}(t)$

$y(t) = y_{0}e^{-4t} + 2$

6 0

3 years ago

Zorah, a musician, pays $120 to have her instrument tuned and $10 per hour for a booth at a fair. She estimates that she earns$2

Lana71 [14]

Answer:

To break-even, Zorah needs to play for 8 hours.

Step-by-step explanation:

<u>To calculate the break-even point in hours, we need to use the following formula:</u>

Break-even point in units= fixed costs/ contribution margin per unit

Break-even point in units= 120 / (25 - 10)

Break-even point in units= 8 hours

To break-even, Zorah needs to play for 8 hours.

5 0

3 years ago

I cut 65 cm off 2 m of rope how much is left

lesantik [10]

2m = 200cm

200cm-65m= 135cm

:)

4 0

3 years ago