Hi- How to solve e^-5x = 0.7658. I need an answer for x??

I don't know if you want to solve by elimination or substitution, so I will choose the easiest;) If you want the other repost and I will do it another way.

2x - y = 4
5x - y = 13

Looking at the equations, the easiest way to solve is by elimination because the y's line up already.

Since the signs on the y's are the same we will subtract the second line from the first line.

2x - y = 4
-(5x -y = 13)
-----------------
-3x = 0 = -9 (2x -5x =-3x, -y--y=0, 4-13=-9)

To get x by itself, divide both sides by -3

-3x = -9
---- ----
-3 -3

x = 3 (negative divided by negative is positive)

To calculate y, put x=3 into either equation. I will put it in the first one.

2 (3) - y = 4
6 - y = 4
y+ 6 - y = 4 + y (I want y positive, so I add y to both sides)
6 = 4 + y
-4 + 6 = 4 + y -4 (I want y by itself, so I subtract 4 from both sides)
2 = y

So my POI (point of intersection) is (3,2)

Normally, a lot of people end there, but I always like to check my answers to prove that I didn't make any silly mistakes.

To do this, I do a left side right side comparison using the equation that I didn't use to solve for the second variable.

Left Side Right Side
5x - y 13
5(3) - 2 13
15 - 2 13
13 = 13
QED

I just proved that I did it all correctly. It the left side didn't equal the right side, I would go back and find my error and recheck it with my left side right side check.

Good luck,

Paul

To evaluate the expression you need the value of x.
To solve you do as follows
ln(5x)=12/4=3
Take the exponential of both sides of ln(5x)=3
e^(ln(5x))=5x=e^(3)
This gives x=(1/5) e^(3)

Can I solve 3x^3 -2x^2+5x=7
5x^3-4x^2+4x=6
4x^3-3x^2+6x=8
These equations by using Casio fx-82ES PLUS Calculator?????

this is a simple algebraic equation in which we have to calculate the value of 'x' using simple operations

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


step 1(pen the brackets) 7+9-5x=10-5x
step 2(add 7 and 9) 16-5x=10-5x

now as 5x gets cancelled both the sides of the equal sign therefore no solution of this algebraic equation exist.

Solve for x
5x+3x+(-15) + 5 becomes 8x-10=180
move 10 from left to right and you get8x190
8x = 190
x = 23.75
so the first angle is (5*23.75)-15 = 103.75
and the second angle is (3*23.75) +5 = 76.25

check by adding 76.25+103.75 = 180

Make sense? I love math, let me know it you need more help

You can solve it with following method.

5x+3y=6 2x-4y=5
So 5x=6-3y so 2[(6-3y)/5]-4y=5
So x=(6-3y)/5 so 12-6y-20y=25
so -26y=25-12
so -26y=13
so y= -(1/2)
2x-4y=5
so 2x=5+4y
so 2x=5+4(-1/2)
so 2x=(10-4)/2
so 2x=6/4
so x =3/2

The value of x=3/2 and value of y= -1/2

Let me know if you need further assistance.
Thanks for using FixYa.

Hello,
Sorry this calculator cannot solve equations. It does not have the program. It does not know how to do those things. However it can calculate. Before you can use the calculator you must prepare all yourself. When you have solved the problem, you ask the calculator to compute the value of what you found.

Let us clean the equation a bit
2(x-4) -5x=-5
Get rid of the parentheses 2(x-4) becomes 2x-2*4=2x-8 .Put that result where it was in equation
2x-8 -5x=-5
Group together the terms that have x in them 2x-5x=-3x
Then
2x-8-5x=-5, becomes -3x-8=-5
You want to isolate the term with x (have it on one side, and the others on the other side) -3x= -5 -(-8)= -5+8 =3.

The equation becomes
-3x=3 Thus -x=3/3=1 and x=-1.
In general you would have obtained x= (some number/some other number) and that is where the calculator would intervene.

Hope it helps.

i think there are programs but with something as simple as that you should be able to work it out manually....
3x+25-5x=5x-5x
-2x+25-25=0-25
-2x=-25
x=25/2 or 12.5

use the simultaneous equation solver software available on ur ti-89 and enter the equation in the form of augmented matrix and you will get ur answer.

Hi joanmae jmeh;

You can add these equations just like you would numbers

3x + 2y = 7
5x - 2y = 1
-----------------------
8x =8
x=1
Now plug x = 1 back into either equation and you can solve for y
Y = 2

When you add the 2 equations together the +2y and the -2y cancel
out

Hope this helps Loringh Please leave a rating for me Thks