Factoring help, please? (2 questions)?

Question

Hi, guys. I need the answers to the following two equations or, at least, how you would go about solving them. Every one MUST be done by factoring, you can't use the quadratic equation or any other method, sadly.

x^2 - 8x = 0 How can I solve it without a 'c' term?

and

2x^2 + 4x - 30 = 0

I narrowed down the factors to 6 and -10 (since the multiply to -30 and add to 4) but when I FOIL the answers I got it doesn't come out correctly. My answers, by the way:

(x + 6) (x - 10)

I also tried (2x + 6) (x - 10) but that didn't work either. What am I doing wrong? Any help is appreciated!

Answer 1

x^2 - 8x = x*(x - 8) = 0
x = 0, 8

2x^2 + 4x - 30 = (2x -6) (x + 5) = 0
x = -5, 3

Answer 2

I got a different answer for 1.
x^2-8x=0
factor out an x x(x-8)=0
divide both sides by x: (x-8)=0
(Division: 0 / x = 0, for nonzero x)

your are left with x-8=0 add x to both sides and you get
x=8

Then put the number in original equation and you get
8^2-(8x8)=0
64-64=0

I also got a different answer for #2
using the foil method, it factors to:
(2x-6)(x+5)=0
I divided both sides by (2x-6) and came up with x+5=0 (since 0/x is zero for any none zero number)
then x=(-5)

To check insert (-5)
2(-5^2)-4(-5)-30=0
2(25)-20-30=0
50-20-30=0

I hope this helps

Answer 3

The 0 product sources says that if 2 (or extra) issues elevated at the same time equivalent 0, one or the different (or both) of the issues are 0. 15x2 = 7x + 2 subtract 7x from both area, subtract 2 from both area. 15x2 - 7x - 2 = 0 to component the trinomial, note (a) you've a minus on the third time period. this suggests your indicators are different. (b) you've a minus connect up your 2d time period, so a more effective decision is linked with the harmful signal) (c) aspects of 15 are a million,15 (not likely, using importance) or 3,5. (d) aspects of two are a million,2. purely write them empty for now (50/50 shot of writing it wisely at this aspect): (3x - )(5x + ) the better decision must be unfavorable. nicely, in case you FOIL 3 and a couple of, that efficient 6 will be higher than the FOIL of one million and 5. you want to attempt it any incorrect way as follows: (3x - 2) (5x + a million) which is going. ***Plug lower back into the equation (3x - 2) (5x + a million) = 0 The 0 product sources says (3x - 2) = 0 OR (5x + a million) = 0 fixing, x = 2/3 or x = -a million/5 the answer set is x = {2/3, -a million/5} (Pls examine that's the answer format your e book needs.) wish that permits.

Answer 4

x²-8x=0
x²=8x
x=8

2x²+4x-30=0
2x²+4x=30
2x(x+2)=30
x+2=15/x
x²+2=15
x²=13
x=root 13

Answer 5

x = 0, 8x = 0, 8
x = -5, 3

Answer 6

1st one is x = 0, 8x = 0, 8 and 2nd one is x = -5, 3

Answer 7

x^2-8x =0
x(x-8)=0
x =0, x-8=0
x=0 , x =8

Second question
2x^2+4x-30=0
x^2 + 2x -15=0
x^2 +5x-3x-15=0
x(x+5)-3(x+5)=0
(x-3)(x+5)=0
x-3=0
x+5=0
x=3,-5

Answer 8

1st one-----------X^2-8X=0
--------------------X(x-8)=0
-------------------either X=0 or X-8=0
------------------------------------X=8

2nd---------2x^2+4x-30=0
-----------2x^2+10x-6x-30=0
-----------2x(x+5)-6(x+5)=0
----------(x+5)(2x-6)=0
-----------x+5=0 or 2x-6=0
----------x=-5 or x=3

Answer 9

(2x+10)(x-3)