All categories

3 years ago

Adding &subtracting negative numbers Evaluate -2+7+(-4).

Mathematics

2 answers:

bija089 [108]3 years ago

5 0

Answer:

= 1

Step-by-step explanation:

− 2 + 7 −4

=5 −4

= 1

navik [9.2K]3 years ago

4 0

Answer: 1

Step-by-step explanation: calculator lol

You might be interested in

HELP ITS THE LAST DAY OF SCHOOL J HAVE 3 MINS

scoray [572]

Answer:

its D

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

What is 3.1 divided by 10.261

Otrada [13]

What is 3.1 divided by 10.261Very simple. We have 2 given decimal number in which our dividend which is the 3.1 is lesser than our divisor which is 10.261.Now, let's start the division to be able to find out what is the quotient we're looking.=> 3. 1 / 10.261 = 0.30.Thus, the quotient is o.30, let's check if we got the correct answer.To check simply do the reverse method=> .30 * 10.261 = 3.1<span>
</span>

6 0

3 years ago

Find the equation of the line passing through points (-4,2) and (1,-6)

anzhelika [568]

Answer:

y + 6 = (-8/5)(x - 1) in point-slope form

Step-by-step explanation:

Moving from the 1st point to the first, we see that x (the 'run') increases by 5 from -4 to 1, and y (the 'rise') decreases by 8. Thus, the slope of the line through these two points is m = rise / run = -8/5

Now we have two points on the line, plus the slope. Let's write out the point-slope formula for the equation of a straight line:

y - k = m(x - h), where (h, k) is a point on the line and m is the slope of the line.

Here, using the point (1, -6), we obtain:

y + 6 = (-8/5)(x - 1) in point-slope form

8 0

2 years ago

A 200-gal tank contains 100 gal of pure water. At time t = 0, a salt-water solution containing 0.5 lb/gal of salt enters the tan

Artyom0805 [142]

Answer:

1) $\frac{dy}{dt}=2.5-\frac{3y}{2t+100}$

2) $y(t)=(50+t)- \frac{12500\sqrt{2} }{(50+t)^{\frac{3}{2} }}$

3) 98.23lbs

4) The salt concentration will increase without bound.

Step-by-step explanation:

1) Let $y$ represent the amount of salt in the tank at time t, where t is given in minutes.

Recall that: $\frac{dy}{dt}=rate\:in-rate\:out$

The amount coming in is $0.5\frac{lb}{gal}\times 5\frac{gal}{min}=2.5\frac{lb}{min}$

The rate going out depends on the concentration of salt in the tank at time t.

If there is $y(t)$ pounds of salt and there are $100+2t$ gallons at time t, then the concentration is: $\frac{y(t)}{2t+100}$

The rate of liquid leaving is is 3gal\min, so rate out is $=\frac{3y(t)}{2t+100}$

The required differential equation becomes:

$\frac{dy}{dt}=2.5-\frac{3y}{2t+100}$

2) We rewrite to obtain:

$\frac{dy}{dt}+\frac{3}{2t+100}y=2.5$

We multiply through by the integrating factor: $e^{\int \frac{3}{2t+100}dt }=e^{\frac{3}{2} \int \frac{1}{t+50}dt }=(50+t)^{\frac{3}{2} }$

to get:

$(50+t)^{\frac{3}{2} }\frac{dy}{dt}+(50+t)^{\frac{3}{2} }\cdot \frac{3}{2t+100}y=2.5(50+t)^{\frac{3}{2} }$

This gives us:

$((50+t)^{\frac{3}{2} }y)'=2.5(50+t)^{\frac{3}{2} }$

We integrate both sides with respect to t to get:

$(50+t)^{\frac{3}{2} }y=(50+t)^{\frac{5}{2} }+ C$

Multiply through by: $(50+t)^{-\frac{3}{2}}$ to get:

$y=(50+t)^{\frac{5}{2} }(50+t)^{-\frac{3}{2} }+ C(50+t)^{-\frac{3}{2} }$

$y(t)=(50+t)+ \frac{C}{(50+t)^{\frac{3}{2} }}$

We apply the initial condition: $y(0)=0$

$0=(50+0)+ \frac{C}{(50+0)^{\frac{3}{2} }}$

$C=-12500\sqrt{2}$

The amount of salt in the tank at time t is:

$y(t)=(50+t)- \frac{12500\sqrt{2} }{(50+t)^{\frac{3}{2} }}$

3) The tank will be full after 50 mins.

We put t=50 to find how pounds of salt it will contain:

$y(50)=(50+50)- \frac{12500\sqrt{2} }{(50+50)^{\frac{3}{2} }}$

$y(50)=98.23$

There will be 98.23 pounds of salt.

4) The limiting concentration of salt is given by:

$\lim_{t \to \infty}y(t)={ \lim_{t \to \infty} ( (50+t)- \frac{12500\sqrt{2} }{(50+t)^{\frac{3}{2} }})$

As $t\to \infty$ , $50+t\to \infty$ and $\frac{12500\sqrt{2} }{(50+t)^{\frac{3}{2} }}\to 0$

This implies that:

$\lim_{t \to \infty}y(t)=\infty- 0=\infty$

If the tank had infinity capacity, there will be absolutely high(infinite) concentration of salt.

The salt concentration will increase without bound.

6 0

3 years ago

30= 2w + 2h<br><br> W= 3/4 h

Alexeev081 [22]

Answer:

h=60/7

w=45/7

Step-by-step explanation:

just try it.

7 0

3 years ago

Read 2 more answers