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3 years ago

6. If F(x) = -6(2x2 + 5x) - 9, what is the value of F(-4)?

Mathematics

1 answer:

Soloha48 [4]3 years ago

5 0

Answer:

-81

Step-by-step explanation:

-6(2x² + 5x) - 9

substitute -4 for 'x'

-6[2(-4)² + 5(-4)] - 9

-6[2(16) + (-20) - 9]

-6(32 - 20) - 9

-6(12) - 9

-72 - 9 = -81

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HELP PLEASE must show work

Setler79 [48]

Answer:

a) 4x -y = 2; (1/2, 0), (0, -2)

b) 3x +y = 5; (5/3, 0), (0, 5)

c) 5x -y = -3; (-3/5, 0), (0, 3)

d) x -y = 7; (7, 0), (0, -7)

e) 8x +y = -12; (-3/2, 0), (0, -12)

Step-by-step explanation:

The form you have is ...

y = -Ax +C . . . . . where B = 1

You can simply rearrange the coefficients to get the form you want.

For (a), you can identify -A = 4, so A = -4, and C = -2. In the desired form, the equation is then ...

-4x +y = -2

"Standard form" requires the leading coefficient be positive, so you now need to multiply the entire equation by -1:

4x -y = 2

I suspect either of the above answers will satisfy your grader, but I like the latter form better. So, the answers below have the equation multiplied by -1 when A is negative to start with.

Since the given equation is already in slope-intercept form, the y-intercept is read directly from the equation as C.

The x-intercept is the value C/A, where you do need to pay attention to the signs.

Again, for (a), the y-intercept is already known to be -2; the x-intercept is ...

C/A = -2/-4 = 2/4 = 1/2.

___

a) A=-4, C=-2, x-intercept = C/A = -2/-4 = 1/2, y-intercept = C = -2. Equation in standard form is 4x -y = 2

b) A=3, C=5, x-intercept = C/A = 5/3, y-intercept = C = 5. Equation in standard form is 3x+y=5

c) A=-5, C=3, x-intercept = C/A = 3/-5 = -5/3, y-intercept = C = 3. Equation in standard form is 5x -y = -3

d) A=-1, C=-7, x-intercept = C/A = -7/-1 = 7, y-intercept = C = -7. Equation in standard form is x -y = 7

e) A=8, C=-12, x-intercept = C/A = -12/8 = -3/2, y-intercept = C = -12. Equation in standard form is 8x +y = -12

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