All categories

3 years ago

Solve the equations by elimination. -7x-8y=9 -4x+9y=-22

Mathematics

1 answer:

Sergeeva-Olga [200]3 years ago

4 0

Solve for x in -7x - 8y = 9

x = -9 + 8y/7

Substitute x = -9 + 8y/7 into -4x + 9y = -22

4(9 + 8y)/7 + 9y = -22

Solve for y in 4(9 + 8y)/7 + 9y = -22

y = -2

Substitute y = -2 into x = -9 + 8y/7

x = 1

Thus,

You might be interested in

Variable definition?

kkurt [141]

The number beside the letter . for example 6x, 6 would be the variable

5 0

3 years ago

Of the 80 boys polled at lunch, 55% say they play video games daily. According to the poll, how many boys play video games daily

alexdok [17]

$55% = \frac{55}{100} = \frac{11}{20}$

Multiply $\frac{11}{20}$ by 80 and you will get how many boys play video games daily.

$\frac{11}{20}*80=\frac{11}{1}*4=11*4=44$

44 is the number of boys who play video games daily.

8 0

3 years ago

Help needed math 3 - 10 points read closely

inessss [21]

<h2>Hello!</h2>

The answer is:

The answer is the fourth option,

$f(-3)=-\frac{1}{3}$

Piecewise functions are functions that are composed by two or more expressions, the expression to use will depend of the domain or input that we need to evaluate.

We are given the piecewise function:

$\left \{ {{\frac{1}{x}, if x$

There, we know that:

We should use the first expression if the value to evaluate is less than -2.

So, for this case, the function will be:

$f(x)=\frac{1}{x}$

We should use the second expression if the value to evaluate is greater or equal than 2.

So, for this case, the function will be:

$f(x)=x^{2}$

Now, since we are given that the value to evaluate is -3, and its less than -2, we need to use the first expression, and evaluate it.

$-3$

So, evaluating the function we have:

$f(x)=\frac{1}{x}$

$f(-3)=\frac{1}{-3}$

$f(-3)=-\frac{1}{3}$

Hence, we have that the answer is the fourth option,

$f(-3)=-\frac{1}{3}$

Have a nice day!

7 0

3 years ago

A duplex generates $1,400 rent for each of its two units per month. The property has been recently appraised for $350,000. What

VLD [36.1K]

The gross income multiplier (GIM) is the ratio of sale price to annual rental income. Here, you have ...
GIM = $350,000/(12*2*$1400) ≈ 10.4

7 0

3 years ago

if it asks for scale factor does that mean i’m supposed to write a ratio? Can someone solve and explain these for me i’m so conf

STatiana [176]

Yes scale factor means ratio. The height of the smaller pyramid to the larger pyramid in ratio form is 8:24 which simplifies to 1:3. The ratio of its areas is the scale factor squared, so 1^2:3^2=1:9. Since the surface area of the smaller pyramid is 124, the surface area of the larger pyramid must be 124x9. The ratio of volumes is the scale factor cubed, so 1^3:3^3=1:27. If the volume of the larger pyramid is 648, then the volume of the smaller pyramid is 1/27 of that, which equals 24.

8 0

3 years ago