. x^3 - 4x^2 - 12x

I think of a balanced scale in my mind when I start these questions. What ever I do to one side, I have to do to the other side to keep it balanced. It starts balanced and I have to keep it balanced.

-(7-4x)=9
(-1) (-1)(7-4x) = 9 (-1) multiply both sides by -1 to get rid of the negative sign
7-4x=-9
7-4x-7=-9-7 subtract 7 from both sides
-4x = -16
-4x = -16
----- ----- divide both sides by -4 to get x by itself
-4 -4
x=4

Check by putting our answer in the original equation and see if the left side is equal to the right side.

Left Side Right Side
-(7-4(4)) 9
-(7-16)
-(-9)
9

Left side = right side

if you mean {7(2)2+[(3-2)-4x(3)]2} or 7(2)2+[(3-2)-4x(3)]2
{28+[(1)-12]2}
{28+[-12]2}
{28+-24}
=4
or if it was 4x not 4 times
{7(2)2+[(3-2)-4x(3)]2}
28+[(1)-12x]2
28+-24x
=-28x+28

See captured image below

4x-(2x-3)=0
=>4x-2x+3=0 ; (after the bracket's oepned and multiplied by - [minus])
=>2x+3=0 ; taken x as common and 4-2=2 i.e. x(4-2) = 2x
=>2x=-3 ; +3's moved on the right-hand side, so it becomes -3
=>x=-3/2 ; 2 has been moved to the right-hand side and divided with -3 i.e 1/2 multiplied by -3 = -3/2

Hence, x = -3/2


Good luck.

Thanks for using FixYa.

Let X=Number of pennies
Then (52-x) =Number of nickels.

You can then say that:

(x*1) + (52-x)(5) = 120
x + 260 - 5x = 120
260 - 4x = 120
260 - 4x + 4x = 120 + 4x
260 = 120 + 4x
260 - 120 = 120 + 4x - 120
140 = 4x
35 = x = Number of pennies
52 - 35 = 17 = Number of nickels
Verify: (35 * .01) + (17 * .05) = $1.20
.35 + .85 = $1.20
$1.20 = $1.20

Hello,
I am not lecturing you but I would rather you understand how to do the manipulations involved in isolating a variable.
You want to isolate y, Ok
Start stripping it of all that is not y.

3y + 4x =6. (Addition is commutative, I can change the order of addition)
The term with y is added to 4x. If I want the term in y alone on one side I perform the inverse operation of addition, a substraction. I subtract 4x from both sides.
3y+4x-4x=6-4x. But 4x-4x=0, and we are left with

3y= - 4x+6

This operation is sometimes summarized as make one term change side while changing its sign

It would do no harm to put the right side of the foregoing equation in parentheses. I do that to avoid errors)

3y= (-4x+6).

Now y is multiplied by the number 3. To isolate y I have to perform the inverse operation of the multiplication, namely the division by 3

3y/3 =(-4x+6)/3. The left hand side is just y

y= (-4x+6)/3.

While result is correct, I can also open the parentheses
y= -4x/3 +6/3
y= -(4/3)*x +2.

Hope it helps.

Hello,
You have the method: apply it.
2 *(3x-4)(4x+5) =(6x-8)(4x+5)
Now apply the FOIL method
F: 6x*4x=24x^2
O: 6x*5=30x
I; -8*4x=-32x
L: -8*5=-40

so the result is
24x^2 + 30x-32x -40 =24x^2 -2x-40

6x+6=4x+12
Since 4x contains the variable to solve for, move it to the left-hand side of the equation by subtracting 4x from both sides.
6x+6-4x=12
Since 6x and -4x are like terms, add -4x to 6x to get 2x.
2x+6=12
Since 6 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 6 from both sides.
2x=-6+12
Add 12 to -6 to get 6.
2x=6
Divide each term in the equation by 2.
(2x)/(2)=(6)/(2)
Simplify the left-hand side of the equation by canceling the common factors.
x=(6)/(2)
Simplify the right-hand side of the equation by simplifying each term.
x=3

Good Luck

sec^4X- sec^2X = 1/cot^4X + 1/cot^2X
RHS
1/cot^4X + 1/cot^2X
=1/(Cos^4X/Sin^4X) + 1/(Cos^2X/Sin^2X)
=Sin^4X/Cos^4X + Sin^2X/Cos^2X
=Sin^4X/Cos^4X + Cos^2X.Sin^2X/Cos^4X
=Sin^2X/Cos^4(Sin^2X + Cos^2X)
=Sin^2X/Cos^4X
=(1-Cos^2X)/Cos^4X
=1/Cos^4X - Cos^2X/Cos^4X
=1/Cos^4X - 1/Cos^2X
=Sec^4X - Sec^2X
=LHS

[3(x-5)-4(-3x+2)]-[4(6-x)]
[(3x-15)-(12x+8)]-(24-4x)
(-9x-23)-(24-4x)
-13x-(-1)
this is 9th grade stuff.