Question

I need help I just don't understand

Answer 1

Answer: 9/7 or -5/2

Step-by-step explanation:

We can only factorise quadratics if they're in the format ax^2 + bx + c

Re-arranging the equation gives 14x^2 + 17x - 45 = 0

Factorising this quadratic gives:

(7x - 9)(2x + 5) = 0

There are numerous ways to factorise quadratics, using a calculator or via alternate methods you may have learnt in class. (E.g. 2 numbers multiply to make (14 * -45) and add up to make (17).

This gives us our solutions.

x = 9/7 or x = -5/2

Answer 2

Answer:

See below.

Step-by-step explanation:

First, move all the terms to one side so we have only a zero on the right:

$6x^2-17x+13=20x^2-32\\-14x^2-17x+45=0\\14x^2+17x-45=0$

(I divided everything by negative 1 in the third step. This is optional, but I like having the first term positive.)

Now, we just need to factor it. To factor, what you want to do is find two numbers a and b such that:

When a and b is multiplied together, they equal the first coefficient and constant multiplied together.

And when a and b is added together, they equal the second term.

In other words, we want to find two numbers that when multiplied equals 14(-45)=-630 and when added equals 17. Then, we can substitute this into the 17. You do this by guessing and checking. It's useful to have a calculator.

After a bit, you can find that 35 and -18 works. Thus:

$14x^2+17x-45=0\\14x^2+35x-18x-45=0\\7x(2x+5)-9(2x+5)=0\\(7x-9)(2x+5)=0$

Now, the finish the problem, we just need to use the Zero Product Property and solve for x:

$2x+5=0\\x=-5/2\\\\7x-9=0\\x=9/7$

Note: This only works for quadratics.