for example like this-
5x-y=33
7x+y=51
2007-12-06 02:58:35 · 6 answers · asked by Cazzie 2 in Science & Mathematics ➔ Mathematics
You have two equations and two unknowns. Use one of the equations to isolate an expression for one of the variables (say, x), then substitute that into the second equation.
5x-y=33
7x+y=51
x = ( 33 + y ) / 5 from the first equation
substituting...
7 ( 33 + y ) / 5 + y = 51
Now you have an equation in one variable; solve for y. Use that answer in either of the original equations to find x.
2007-12-06 03:05:51 · answer #1 · answered by jgoulden 7 · 0⤊ 0⤋
Let's use substitution.
5x-y=33
7x+y=51
5x-y=33
y = 5x - 33
Now, the next equation:
7x + y = 51 {Put 5x-33, from above, for y}
7x + (5x-33) = 51
11x - 33 = 51
12x = 84
x = 7
Now, y=5x - 33; x=7
y = 5(7) - 33
y = 2
Check it. Use 7 for x and 2 for y in your original equations, and see if the equations are true.
2007-12-06 03:04:18 · answer #2 · answered by Hiker 4 · 0⤊ 0⤋
5x - y = 33
5x = y + 33
x = (y + 33)/5
7x + y = 51
7x = 51 - y
x = (51 - y)/7
Find y:
(y + 33)/5 = (51 - y)/7
7(y + 33) = 5(51 - y)
7y + 231 = 255 - 5y
12y = 24
y = 2
Answer: y = 2
Proof:
Find x:
= (2 + 33)/5
= 2/5 + 33/5
= 35/5
= 7
5(7) - 2 = 33
35 - 2 = 33
7(7) + 2 = 51
49 + 2 = 51
2007-12-06 04:02:07 · answer #3 · answered by Jun Agruda 7 · 3⤊ 0⤋
Solve For Y
2016-09-28 21:16:50 · answer #4 · answered by lil 4 · 0⤊ 0⤋
This is probably easiest to solve using elimination.
just add the two together to get:
12x=84 (the y's drop out)
then x = 7 so,
7*7+y=51 (substituting 7 for x into the second equation)
49+y=51
y=2
2007-12-06 03:08:16 · answer #5 · answered by grompfet 5 · 0⤊ 0⤋
5x-y=33
7x+y=51
I suggest to add the equations together to get
12x = 84
x = 7
Substitute x into first equation to solve for y
5x - y= 33
5(7) - y = 33
-y = -2
y = 2
.
.
2007-12-06 03:10:28 · answer #6 · answered by Robert L 7 · 1⤊ 1⤋
Simplifying
5x + -1y = 33
Solving
5x + -1y = 33
Move all terms containing y to the left, all other terms to the right.
Add '-5x' to each side of the equation.
5x + -5x + -1y = 33 + -5x
Combine like terms: 5x + -5x = 0
0 + -1y = 33 + -5x
-1y = 33 + -5x
Divide each side by '-1'.
y = -33 + 5x
Simplifying
y = -33 + 5x
Simplifying
7x + y = 51
Solving
7x + y = 51
Move all terms containing y to the left, all other terms to the right.
Add '-7x' to each side of the equation.
7x + -7x + y = 51 + -7x
Combine like terms: 7x + -7x = 0
0 + y = 51 + -7x
y = 51 + -7x
Simplifying
y = 51 + -7x
2007-12-06 03:07:07 · answer #7 · answered by Anonymous · 0⤊ 0⤋