Question

solve the indicated set: (3x+5)(2x-8)=0

Answer 1

Any ideas?

Answer 2

factoring?

Answer 3

You are on the right track...

Answer 4

6x^2 -14x+40=0

Answer 5

-40

Answer 6

...but you already have two factors:
one is (3x+5)
and the other is (2x-8)

Answer 7

so do you make both of them equal to 0?

Answer 8

Yes.

Answer 9

will the answers be rational reals?

Answer 10

Yes.

Answer 11

x=4, -5/3

Answer 12

Yes, either x=4 or x=-5/3 will make (3x+5)(2x-8)=0 a true statement, right?

Answer 13

Can you tell me why?

Answer 14

Is it just an accident that the opposite of the numbers divided is the answer?
ex. (2x-8) -8 and 2

Answer 15

x=4 or x=-5/3 are the solutions to the equation: $$\Huge (3x+5)(2x-8)=0 $$

Answer 16

Let x = 4, substitute that value of x into the equation, what do you get?

Answer 17

0

Answer 18

Yes, you get 0 on the left hand side because 0 times any number is 0, and because there is a 0 on the right hand side you get the true statement 0 = 0, right?

Answer 19

yes

Answer 20

The same applies for the other solution x = -5/3

Answer 21

Thus the solution set is {4, -5/3}

Answer 22

ok thank you!

Answer 23

Thanks for trying to learn.