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4 years ago

If 4m-7n=10 and 2m+2n=4, what is the value of 2m-9n?

1 answer:

3 0

4m - 7n = 10
2m + 2n = 4 - multiply everything by -1.

4m - 7n = 10
-2m - 2n = -4 Add the 2 equations

(4m - 7n = 10)
+(-2m - 2n = -4)
-------------------------
2m - 9 n = 6.

The value of 2m - 9n would be 6.

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3x-10-4

snow_lady [41]

Answer/Step-by-step Explanation:

1. 3x - 10 +4 if x = 3

To evaluate, plug in the value of x in the expression given

3(3) - 10 + 4 = 9 - 10 + 4

= 3

2. $\frac{x}{2} + 6x$

if x = -12

$\frac{(-12)}{2} + 6(-12)$

- 6 - 72 = - 78

3. 8(x - y), if x = 2, y = 6

8(2 - 6) = 8(-4) = -32

4. x + xy, if x = 3, y = -2.5

3 + (3)(-2.5) = 3 + (-7.5)

= 3 - 7.5 = - 4.5

5. (2x)² + 6, if x = -2

(2*-2)² + 6 = (-4)² + 6

= 16 + 6 = 22

6. 3x + 4y - 3x, if x = 2, y = 4

3(2) + 4(4) - 3(2) = 6 + 16 - 6

= 16

7. $-10x + \frac{4}{x}$

If x = -2

$-10(-2) + \frac{4}{-2}$

20 + (-2) = 20 - 2 = 18

8. 3(8x - 10) + 5x, if x = ½

3(8*½ - 10) + 5(½)

3(4 - 10) + 2.5

3(-6) + 2.5 = -18+2.5 = - 20.5 or 20½

9. x + 8y - (x)², if x = -5, y = ¼

-5 + 8(¼) - (-5)² = -5 + 2 - (25)

= -3 - 25 = -28

10. (8x)² + 6x + 2, if x = -3

(8*-3)² + 6(-3) + 2 = (-24)² - 18 + 2

= 576 - 18 + 2 = 560

11. 2x² + 4y² + xy, if x = ½, y = 2

2(½)² + 4(2)² + (½)(2)

= 2(¼) + 4(4) + 1

= ½ + 16 + 1 = ½ + 17 = 17½

12. 8x + 2y, if x = 1.5, y = -2.2

8(1.5) + 2(-2.2)

12 - 4.4 = 7.6

13. $\frac{5}{2}(x - 6) + 4$

if x = 8.

$\frac{5}{2}(8 - 6) + 4$

$\frac{5}{2}(2) + 4$

= 5 + 4 = 9

14. 3x - 8x² + 7, if x = 4.5

3(4.5) - 8(4.5)² + 7

13.5 - 8(20.25) + 7

13.5 - 162 + 7 = -141.5

15. -2x² + 8y, if x = 3, y = -9

-2(3)² + 8(-9)

-2(9) - 72 = - 18 - 72 = 90

16. (-5x)² - 3x + x, if x = -3.5

(-5*-3.5)² - 3(-3.5) +(-3.5)

(17.5)² + 10.5 - 3.5

306.25 + 10.5 - 3.5 = 313.25

8 0

3 years ago

Help me find y please

Andreyy89

Answer:

103

Step-by-step explanation:

it has to add up to 180 so

180-77=103

3 0

3 years ago

Determine the value of n that makes the polynomial a perfect square trinomial. Then factor as the square of a binomial. Express

blsea [12.9K]

Answer:

Step-by-step explanation:

$y^2-11y+n\\=(y-(11/2))^2+n-(11/2)^2$

So in order the trinomial a perfect square we need

$n-(11/2)^2 =0\\n= (11/2)^2\\n=\frac{121}{4}$

When n is equal to this number that we have

$y^2-11y+n = (y- (11/2))^2$

6 0

3 years ago

Given the expression (8 + 6i) − (−2 + 7i), perform the indicated operation and write the answer in the form a + bi

Oliga [24]

We can distribute the negative to get 8 + 6i + 2 - 7i, and we can simplify that to get 10 - i.
---
Hope this helps!

6 0

3 years ago

Identify the vertex, the axis of symmetry, the maximum or minimum value, and the range of the parabola for y=x^2+6x+13

charle [14.2K]

Answer:

Step-by-step explanation:

First we can determine the x value of our vertex via the equation:

$x=\frac{-b}{2a}$

Note that in general a quadratic equation is such that:

$ax^2+bx+c$

In this case a,b and c are the coefficients and so a=1, b=6 and c=13.

Therefore we can determine the x component of the vertex by plugging in the values known and so:

$x=\frac{-b}{2a}=\frac{-6}{2(1)}=\frac{-6}{2}=-3$

Now we can determine the y-component of our vertex by plugging in the x-component to the equation and so:

$f(x)=x^2+6x+13\\\\f(-3)=(-3)^2+6(-3)+13\\\\f(-3)=4$

Therefore our vertex is (-3,4). Now in vertex our x component determines is the axis of symmetry so the equation for axis of symmetry is:

x=-3

Similarly, the y-component of our vertex is the minimum or maximum. In this case it is the minimum you can determine this because a is positive meaning that the parabola will point up, and so the equation for the minimum is:

y=4

The range of the formula is the smallest y-value meaning the minimum y=4 and all real numbers that are more than 4, mathematically:

Range = All real numbers greater than or equal to 4.

4 0

4 years ago