When factorising a quadratic trinomial of the form ax^2 + bx + c, we need to find two numbers which ???? (see image for options)

Mathematics

1 answer:

kupik [55]3 years ago

3 0

Answer: Choice E

multiply to give a*c and add to get b

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This is known as the AC factoring method based on how you multiply the first and last coefficients (a and c) and use that product to figure out which factors add to the middle coefficient.

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An example:

6x^2 + 35x + 50

We have a = 6, b = 35, c = 50

Multiply a and c and we get: a*c = 6*50 = 300

We need to find factors of 300 that pair up and add to 35

Through trial and error you should find,

15 * 20 = 300

15 + 20 = 35

The two numbers are therefore 15 and 20.

So we break 35x into 15x+20x and use the factor by grouping method

6x^2 + 35x + 50

6x^2 + 15x + 20x + 50

(6x^2 + 15x) + (20x + 50)

3x(2x + 5) + 10(2x + 5)

(3x + 10)(2x + 5)

We see that 6x^2 + 35x + 50 factors to (3x + 10)(2x + 5)

Use the FOIL method or the box method or distribution to help see that (3x + 10)(2x + 5) expands back to 6x^2 + 35x + 50.

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Write the equation of line AB in slope-intercept form, given the points A(0,5) and B(-5,-10) . In your final answer, include all

Evgesh-ka [11]

Answer:

y = 3x + 5

Step-by-step explanation:

1) First, find the slope between the pair of points. Use the slope formula $m = \frac{y_2-y_1}{x_2-x_1}$ . Substitute the x and y values of points A and B into the formula and simplify:

$m = \frac{(-10)-(5)}{(-5)-(0)} \\m = \frac{-10-5}{-5-0} \\m = \frac{-15}{-5} \\m = 3$

So, the slope is 3.

2) Now, identify the y-intercept of the line, or the point at which the line intersects the y-axis. All points on the y-axis have an x-value of 0. We're told that (0,5) is a point the line intersects, and since it has an x-value of 0, that must be the y-intercept.

3) Using slope-intercept format, represented by the equation $y = mx + b$ , write the equation of the line. Remember that the number in place of $m$ , or the coefficient of the x-term, is the slope. So, substitute 3 for $m$ . Also, remember that $b$ represents the y-intercept of a line, so substitute 5 in its place, too. This gives the following answer: