Algebra Help?

Question

i need the ways to solve the problems more than the answers
1. (x+3)(x-3)
2.y=3x
2x-2y=8
3.4x(2x-4)

number 2 has two lines there is no 2

Answer 1

You need to talk to a math teacher for some time. These are not difficult, they just take time.

Answer 2

well the first one you need to foil (which means multiply First, Outside, Inside, Last) and then the problem would look like this:
x^2-3x+3x-9 which simplified is x^2-9. or if you just need to find x then set each set of () equal to zero and then x can equal either number.
the second one you can use substitution method on so if y=3x then plug this into the equation which then reads:
2x-2(3x)=8, which simplified is 2x-6x=8 which simplified again is:
-4x=8 and then you can solve it from there.
i take it in the third one that you are trying to solve for x so you can set it up like the first one (with each equal to zero) and solve for x that way. it would look something like this:
4x=0, 2x-4=0 and then on the first set, divide by four and you get 0/4 which is 0 and then on the second set subtract four which would give you 2x=-4 and then divide by -2 to get the x alone. then the answer would be written: x=(#), x=(3).
hope this helps you get all of the answers!!!
Best of luck in school!

Answer 3

1. (x + 3)(x - 3)

Use FOIL, which stands for first, outside, inside, last. You multiply them in that order.

[x * x] + [-3 * x] + [3 * x] + [-3 * 3]
x^2 -3x + 3x -9
x^2 -9

2. y =3x

Just pretend y is a number, not a variable.

y=3x
y / 3 = x

3. x - 2y = 8

Solve just as if the y was a number, not a variable.

x = 2y + 8

4. 4x(2x - 4)

When multiplying a number by a binomial, be sure to multiply EACH term.

[4x * 2x] + [4x * -4]
8x^2 - 16x

There you go.

Answer 4

Are these all part of the same sum?
Substitute what you know - if y = 3x, then everytime there's a y put in 3x, solve for x and once you have x, solve for y.
Obviously, you can't solve for anything in problems 1 and 4 because they don't equal anything. You would need to know, for example that 4x(2x-4)= 0

Answer 5

1. (x+3)(x-3) foil method
first, outer, inter, last
multiply the first two number or letters in () then add or subtract (depends on the sign + or -)...
here....

X^2 -3X+3X-9

2.y=3x
2x-2y=8
Solve the first equation for x in terms of Y then do direct subsitution into the next equation and solve for Y. Use that answer to go back and solve for X

Or solve for Y first, which is easier in this case
hint: 2X-2*(3X) =8

3.4x(2x-4)

Distributive property
(4X*2X) + (4X*-4)

Answer 6

1 (x + 3)(x - 3) = x*x + 3*x - 3*x + 3*-3= x^2-9

2
(y = 3x)2=2y-6x=0 Vbring down
2x - 2y = 8
2y-6x=0 now add the equations
-4x =8 now divide by -4
x = -2

3 4x(2x-4) = 4x*2x - 4x*4 = 8x^2 - 16x

Answer 7

1. use FOIL (Firsts-Outers-Inners-Lasts) so you get x^2-9
2. That's not a problem just an equation which i'm assuming you have to graph
3. Divide the equation by 2 so you get x-y=8, then you can make that y=-8x
4.What are they asking you to do for 4?

Answer 8

if all you have to do is solve for "x" than

(x+3)(x-3) you need to know FOIL. first, outside, inside, last

first... x times x = x2
outside -3 times x = -3x
inside 3 times x = 3x
last 3 x 3 = 9

so you have x2 + 3x -3x + 9
which shortens to x2 + 9
so x = 3

i'm sure you can figure out the others based on this... good luck
study hard!

josh

Answer 9

Distributive property:
Step by step
1. x*x +3x-3x-9 = x^2-9

2. if y= 3x then plug 3x into the 2nd equation where y is, so you would get... 2x-2(3x)=8.....2x-6x=8.....-4x=8....x= -2

3. multiply the 4x by both the terms inside the parentheses
(4x*2x)-(4x*4)....8x^2-16x

Answer 10

(3x)(-3x) =1.0 or 1.x ?


2x - 2y =8 x is 8 and y is 4 2x8=16 2x4=8 16-8=8

3.4x(-2x)=?

Answer 11

wow, this is a good way to get any answers to any questions.. sorwie couldn't help ya buddy.. try solving x first then replace x with the given problem..