All categories

3 years ago

Y = 7x + 9 2y + 2x = -18

Mathematics

2 answers:

Fofino [41]3 years ago

8 0

Answer:

x=-9/4, y=-27/4. (-9/4, -27/4).

Step-by-step explanation:

y=7x+9

2y+2x=-18

----------------

simplify 2y+2x=-18 into y+x=-9

------------------

7x+9+x=-9

8x+9=-9

8x=-9-9

8x=-18

x=-18/8

simplify

x=-9/4

y=7(-9/4)+9=-63/4+9=-27/4

zvonat [6]3 years ago

5 0

Answer:

Step-by-step explanation:

Just multiply the first equation by -1 and then add them together to find x. Should look something like

-2x - y = -7

5x + y = 9

--------------------

3x + 0 = 2

x = 2/3

Now back substitute using either equation to find y. I'll use the first:

2(2/3) + y = 7

4/3 + y = 7

y = 7 - 4/3 = 21/3 - 4/3 = 17/3

Answer:

x=2/3

y=17/3

You might be interested in

What does math means

Virty [35]

Answer:

short for mathematics, also "Master of arts in theology"

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

HELPPPP PLEASE I will give brainliest and I put it up for 100 points

Mamont248 [21]

..................✨✨✨✨✨✨✨✨✨✨✨✨✨✨

8 0

2 years ago

Read 2 more answers

Help pleasee find the point slope form find the slope intercept form

pav-90 [236]

The slope is 2/3 since the slope formula is y=mx+b the mx is we’re the slope y-int is.

7 0

3 years ago

Heartbeat takes 0.8 seconds.how many seconds is this written as a fraction?

liubo4ka [24]

0.8 = 8/10

simplified = 4/5 seconds

hope this helps

5 0

4 years ago

Read 2 more answers

Find the two intersection points

bogdanovich [222]

Answer:

Our two intersection points are:

$\displaystyle (3, -2) \text{ and } \left(-\frac{53}{25}, \frac{46}{25}\right)$

Step-by-step explanation:

We want to find where the two graphs given by the equations:

$\displaystyle (x+1)^2+(y+2)^2 = 16\text{ and } 3x+4y=1$

Intersect.

When they intersect, their x- and y-values are equivalent. So, we can solve one equation for y and substitute it into the other and solve for x.

Since the linear equation is easier to solve, solve it for y:

$\displaystyle y = -\frac{3}{4} x + \frac{1}{4}$

Substitute this into the first equation:

$\displaystyle (x+1)^2 + \left(\left(-\frac{3}{4}x + \frac{1}{4}\right) +2\right)^2 = 16$

Simplify:

$\displaystyle (x+1)^2 + \left(-\frac{3}{4} x + \frac{9}{4}\right)^2 = 16$

Square. We can use the perfect square trinomial pattern:

$\displaystyle \underbrace{(x^2 + 2x+1)}_{(a+b)^2=a^2+2ab+b^2} + \underbrace{\left(\frac{9}{16}x^2-\frac{27}{8}x+\frac{81}{16}\right)}_{(a+b)^2=a^2+2ab+b^2} = 16$

Multiply both sides by 16:

$(16x^2+32x+16)+(9x^2-54x+81) = 256$

Combine like terms:

$25x^2+-22x+97=256$

Isolate the equation:

$\displaystyle 25x^2 - 22x -159=0$

We can use the quadratic formula:

$\displaystyle x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

In this case, a = 25, b = -22, and c = -159. Substitute:

$\displaystyle x = \frac{-(-22)\pm\sqrt{(-22)^2-4(25)(-159)}}{2(25)}$

Evaluate:

$\displaystyle \begin{aligned} x &= \frac{22\pm\sqrt{16384}}{50} \\ \\ &= \frac{22\pm 128}{50}\\ \\ &=\frac{11\pm 64}{25}\end{aligned}$

Hence, our two solutions are:

$\displaystyle x_1 = \frac{11+64}{25} = 3\text{ and } x_2 = \frac{11-64}{25} =-\frac{53}{25}$

We have our two x-coordinates.

To find the y-coordinates, we can simply substitute it into the linear equation and evaluate. Thus:

$\displaystyle y_1 = -\frac{3}{4}(3)+\frac{1}{4} = -2$

And:

$\displaystyle y _2 = -\frac{3}{4}\left(-\frac{53}{25}\right) +\frac{1}{4} = \frac{46}{25}$

Thus, our two intersection points are:

$\displaystyle (3, -2) \text{ and } \left(-\frac{53}{25}, \frac{46}{25}\right)$

6 0

3 years ago