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Breaking apart a quadratic expression into a pair of binomials is called:
deconstructing |
|
factoring |
|
squaring |
|
normalizing |
To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.
Find the value of a:
-4a + y = -5
7a + 9y = 8
| -1\(\frac{26}{53}\) | |
| -3\(\frac{1}{3}\) | |
| 1\(\frac{2}{45}\) | |
| 1\(\frac{10}{43}\) |
You need to find the value of a so solve the first equation in terms of y:
-4a + y = -5
y = -5 + 4a
then substitute the result (-5 - -4a) into the second equation:
7a + 9(-5 + 4a) = 8
7a + (9 x -5) + (9 x 4a) = 8
7a - 45 + 36a = 8
7a + 36a = 8 + 45
43a = 53
a = \( \frac{53}{43} \)
a = 1\(\frac{10}{43}\)
The endpoints of this line segment are at (-2, 4) and (2, 2). What is the slope-intercept equation for this line?
| y = x + 3 | |
| y = -\(\frac{1}{2}\)x + 3 | |
| y = 2\(\frac{1}{2}\)x + 3 | |
| y = \(\frac{1}{2}\)x - 4 |
The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is 3. The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 4) and (2, 2) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(2.0) - (4.0)}{(2) - (-2)} \) = \( \frac{-2}{4} \)Plugging these values into the slope-intercept equation:
y = -\(\frac{1}{2}\)x + 3
What is 8a - 9a?
| 72a2 | |
| 72a | |
| -1a | |
| a2 |
To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.
8a - 9a = -1a
Solve for z:
z2 + 18z + 68 = z - 4
| -2 or -7 | |
| 6 or 6 | |
| 9 or 1 | |
| -8 or -9 |
The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:
z2 + 18z + 68 = z - 4
z2 + 18z + 68 + 4 = z
z2 + 18z - z + 72 = 0
z2 + 17z + 72 = 0
Next, factor the quadratic equation:
z2 + 17z + 72 = 0
(z + 8)(z + 9) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 8) or (z + 9) must equal zero:
If (z + 8) = 0, z must equal -8
If (z + 9) = 0, z must equal -9
So the solution is that z = -8 or -9