Answer:
a = -86.
Step-by-step explanation:
By the Factor Theorem, if x + 4 is a factor then P(-4) = 0, so:
P(-4) = 2(-4)^3 - 11(-4)^2 + a(-4)- 40 = 0
-128 - 176 - 4a - 40 = 0
-4a = 128 +176 + 40
-4a = 344
a = -86.
Solve the following system using elimination:
{7 x + 2 y = -19 | (equation 1)
{2 y - x = 21 | (equation 2)
Add 1/7 × (equation 1) to equation 2:
{7 x + 2 y = -19 | (equation 1)
{0 x+(16 y)/7 = 128/7 | (equation 2)
Multiply equation 2 by 7/16:
{7 x + 2 y = -19 | (equation 1)
{0 x+y = 8 | (equation 2)
Subtract 2 × (equation 2) from equation 1:
{7 x+0 y = -35 | (equation 1)
{0 x+y = 8 | (equation 2)
Divide equation 1 by 7:
{x+0 y = -5 | (equation 1)
{0 x+y = 8 | (equation 2)
Collect results:
Answer: {x = -5, y = 8
x | y
——-
-10|-18
-9 |-17
-8 |-16
-7 |-15
-6 |-14
-5 |-13
-4 |-12
-3 |-11
-2|-10
-1 | -9
0 | -8
1 | -7
2 |-6
3 | -5
4 | -4
5 | -3
6 | -2
7 | -1
8 | 0
9 | 1
10| 2
Beforehand let me apologize for my sloppy handwriting. I'm a lefty, so please deal with me. . Anyway, the equation you listed didn't really have a x, because a linear equation is y= mx+b, and anything with x is the slope. But I did see y and a number on one side, so I'm like maybe I can get these two alone. So here's what I did:
2y + 4=0
-4 -4 I subtracted 4 on both sides. Why because you would want "y" alone.
Next,
2y= -4
Now to get "y" alone you want to divide on both sides.
2y= -4/ 2
y= -2
Now you're probably thinking "how do you graph it? There's no "x" in the equation." Well, you just graph it. Since the answer is y= -2, you go to the y axis, look for -2, and place a line to indicate that is the equation. And to make it clear, remember y is the y-intercept.
I really do hope this helps you, if not message me. I'll be happy to help, and again I'm sorry for my handwriting!