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iragen [17]
3 years ago
12

Use substitution to solve the following system of equations. 9x + 5y = 32 AND y = -3x + 4

Mathematics
1 answer:
Darya [45]3 years ago
4 0

Answer:

x = -2

y = 10

Step-by-step explanation:

Since they already gave y as -3x +4, you will then have to substitute that amount into the formula

9x + 5y = 32

By doing that you get

9x +5(-3x+4) = 32

9x -15x +20 = 32

Then, you ill take 20 to the other side to subtract 32, which will get you

-6x = 12

Then, you will get x = -2

Then substitute that for the equation

y = -3x + 4

You will get

y = -3(-2) + 4,

You will get y as 10

SO then your final answer is x = -2, y = 10

You might be interested in
What is an equation of the line that passes through the point (8,-5) and is parallel
HACTEHA [7]

Answer:

y=-5/4x+5

Step-by-step explanation:

Hi there!

We're given the line 5x+4y=24 and we want to find the line parallel to it that passes through (8,-5)

Parallel lines have the same slopes

First, we need to find the slope of 5x+4y=24.

We'll do that by converting 5x+4y=24 from standard form (ax+by=c where a, b, and c are integers) to slope-intercept form (y=mx+b where m is the slope and b is the y intercept)

subtract 5x from both sides

4y=-5x+24

divide by 4 on both sides

y=-5/4x+6

since -5/4 is in the place where m should be, it is the slope.

So the equation of the line parallel to it will also have -5/4 as the slope

Here's the equation so far in slope-intercept form:

y=-5/4x+b

we need to find b

because the equation will pass through (8,-5), we can use it to solve for b

substitute 8 as x and -5 as y

-5=-5/4(8)+b

multiply

-5=-10+b

add 10 to both sides

5=b

substitute 5 as b into the equation

<u>y=-5/4x+5</u>

That's the equation of the line parallel to 5x+4y=24.

Hope this helps!

6 0
3 years ago
A line tangent to the curve f(x)=1/(2^2x) at the point (a, f(a)) has a slope of -1. What is the x-intercept of this tangent?
kirza4 [7]

Answer:

x-intercept = 0.956

Step-by-step explanation:

You have the function f(x) given by:

f(x)=\frac{1}{2^{2x}}   (1)

Furthermore you have that at the point (a,f(a)) the tangent line to that point has a slope of -1.

You first derivative the function f(x):

\frac{df}{dx}=\frac{d}{dx}[\frac{1}{2^{2x}}]  (2)

To solve this derivative you use the following derivative formula:

\frac{d}{dx}b^u=b^ulnb\frac{du}{dx}

For the derivative in (2) you have that b=2 and u=2x. You use the last expression in (2) and you obtain:

\frac{d}{dx}[2^{-2x}]=2^{-2x}(ln2)(-2)

You equal the last result to the value of the slope of the tangent line, because the derivative of a function is also its slope.

-2(ln2)2^{-2x}=-1

Next, from the last equation you can calculate the value of "a", by doing x=a. Furhtermore, by applying properties of logarithms you obtain:

-2(ln2)2^{-2a}=-1 \\\\2^{2a}=2(ln2)=1.386\\\\log_22^{2a}=log_2(1.386)\\\\2a=\frac{log(1.386)}{log(2)}\\\\a=0.235

With this value you calculate f(a):

f(a)=\frac{1}{2^{2(0.235)}}=0.721

Next, you use the general equation of line:

y-y_o=m(x-x_o)

for xo = a = 0.235 and yo = f(a) = 0.721:

y-0.721=(-1)(x-0.235)\\\\y=-x+0.956

The last is the equation of the tangent line at the point (a,f(a)).

Finally, to find the x-intercept you equal the function y to zero and calculate x:

0=-x+0.956\\\\x=0.956

hence, the x-intercept of the tangent line is 0.956

5 0
3 years ago
What is the arc measure of BDC in degrees?<br> (4k + 159)<br> P<br> (2k + 153)
andre [41]
<h2>Explanation:</h2><h2></h2>

The diagram is missing but I'll assume that the arc BDC is:

(4k + 159)^{\circ}

And another arc, let's call it FGH. measures:

(2k + 153)^{\circ}

If those arc are equal, then this equation is true:

(4k + 159)^{\circ}=(2k + 153)^{\circ} \\ \\ (4k + 159)=(2k + 153) \\ \\ \\ Solving \ for \ k: \\ \\ 4k-2k=153-159 \\ \\ 2k=-6 \\ \\ k=-\frac{6}{2} \\ \\ k=-3

Substituting k into the first equation:

\angle BDC=(4(-3)+159)^{\circ} \\ \\ \angle BDC=(-12+159)^{\circ} \\ \\ \boxed{\angle BDC=147^{\circ}}

3 0
3 years ago
Read 2 more answers
Best answer or correct answer gets brainliest
Brilliant_brown [7]

Answer: C. x = 6; m∠XOY = 18

Step-by-step:

We see that ZOW and WOX are supplementary, meaning the sum of their angles equal 180.

We also know that WOY is a right angle and equals 90.

Now we can solve

180-108 = 72

90 - 72 = 18

XOY = 18

Because 3x = 18, we know that x = 18 by dividing 18 by 3

5 0
3 years ago
On Kathleen's credit card statement get last balance was $89.70. She made a payment of $20, had new charges totaling $32.11, and
Leona [35]
Hi there

Amount financed
89.70−20=69.7

Finance charge
69.7×(0.0123)=0.86

New balance
Previous balance-payment+finance charge+New charge (new transaction)
89.7−20+0.86+32.11
=102.67

Hope it helps
5 0
3 years ago
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