All categories

3 years ago

Math (10 points) please help

Mathematics

1 answer:

Eddi Din [679]3 years ago

3 0

Answer:

x = - 1, y = 4

Step-by-step explanation:

A. We are going to use elimination method because we have +2y and -2y, and when we add these equations +2y and -2y are going to be eliminated.

x + 2y = 7

+ 3x - 2y = -11

4x = - 4

x = - 1

x + 2y = 7

-1 + 2y = 7

2y = 8

y = 4

You might be interested in

Help answer this if ya know!

blagie [28]

C) The +10 is because you already have 10 coins, that will not change. The 6x is because with each passing day, the number of coins increase by 6 (x represents days). The equation then turns into y=6x+10

Hope this helps comment for more questions :)

4 0

3 years ago

X-5y-z=-20 -2x-y-6z=25 -x-4y-z=-15 Solve by elimination

Tju [1.3M]

Answer:

x = 0

y = 5

z = -5.

Step-by-step explanation:

X-5y-z=-20

-2x-y-6z=25

-x-4y-z=-15

Add equation 1 and 3:

-9y - 2z = -35 .......... A

Multiply the first equation by 2:

2x - 10y - 2z = -40

Now add this to equation 2:

-11y -8z = -15.............B

Now multiply equation A by -4:

36y + 8x = 140.........C

Add equations B and C:

25y = 125

y = 5.

Substitute for y in equation A:

-9*5 - 2z = -35

2z = -45 + 35 = - 10

z = -5.

Now find x by substituting for y and z in the first equation:

x - 5(5) - (-5) = -20

x - 20 = -20

x = 0.

6 0

3 years ago

Find the value of x.

konstantin123 [22]

Answer:

x= 37.5°

Step-by-step explanation:

∠CBD

= 180° -75° (adj. ∠s on a str. line)

= 105°

∠BCD= ∠BDC (base ∠s of isos. △BCD)

∠BCD= x

∠BCD +∠BDC +∠CBD= 180° (∠ sum of △BCD)

x +x +105°= 180°

2x= 180° -105°

2x= 75°

x= 37.5°

Alternative working:

∠BDA= (180° -75°) ÷2 (base ∠s of isos. △ABD)

∠BDA= 52.5°

∠BDA +∠BDC= 90°

52.5° +x= 90°

x= 90° -52.5°

x= 37.5°

6 0

3 years ago

Math question please help If you get this right I will mark you as a brainliest

mixas84 [53]

What do you need help with

8 0

3 years ago

Lucy had math and reading homework tonight. Lucy can solve each math problem in 5 minutes and she can read each page in 2.5 minu

drek231 [11]

Answer:

$x=18,y=6$ , graph is there for reference.

Step-by-step explanation:

Given,

$x$ is the number of math problem Lucy solved.

$y$ is the number of pages she read.

She can do each math problem in $5$ minutes, therefore she can solve $x$ number of questions into $5 \times x=5x$ minutes.

She can read each page in $2.5$ minutes, therefore she can read $y$ pages in 2.5y minutes.

As per given detail,

$5x+2.5y=105$ equation 1.

And,

It is given that number of math problems Lucy solved is 3 times the number of pages she read.

$x=3y$ equation 2.

We need to find $x$ and $y$ intercept of each of the equation to graph them.

For $x-intercept$ put y=0

We will get $x=\frac{105}{5} =21$

Thus the point is $(21,0)$

Let us find $y-intercept$ by assuming $x=0$

we get $y=\frac{105}{2.5} =42$

Thus the point is $(42,0)$

Join these two points.

Similarly considering the other equation $x=3y$

Here x-intercept would be at $y=0$

We will get $x=0$

Thus the point is $(0,0)$

Let us assume on more point, say $x=30$ , we get $y=10$

Thus the point is $(30,10)$

Join these two points.

We will get a point of intersection at $(18,6)$

Thus $x=18$ and $y=6$

8 0

3 years ago