SOLUTION: I need help using the substitution method so can you help me solve this problem:
3x+5y=-3
-3x+y=-15
I also need help using the combination method so maybe with these too:
1) 4x
Algebra.Com
Question 27808: I need help using the substitution method so can you help me solve this problem:
3x+5y=-3
-3x+y=-15
I also need help using the combination method so maybe with these too:
1) 4x+5y=-2
5x=5-10y
2) 3y=16-2x
5x+2y=14
Last question is on graphing inequalities, i think:
4x+3y (is less then or equal to) 13
-3x+4y>9
Answer by sdmmadam@yahoo.com(530) (Show Source): You can put this solution on YOUR website!
I need help using the substitution method so can you help me solve this problem:
3x+5y=-3
-3x+y=-15
I also need help using the combination method so maybe with these too:
1) 4x+5y=-2
5x=5-10y
2) 3y=16-2x
5x+2y=14
Last question is on graphing inequalities, i think:
4x+3y (is less than or equal to) 13
-3x+4y(is greater than or equal to) 9
1)Substitution method:
3x+5y=-3 ----(1)
-3x+y=-15 ----(2)
From (2), we have y = 3x-15 ----(*)
(adding 3x to both the sides or transferring -3x from LHS to RHS, change side then change sign)
Substituting for y in (1),
3x + 5(3x-15) = -3
3x +5X3x - 5X15 = -3
3x+15x -75 =-3
18x = -3+75
18x = 72
x = 72/18 = (18X4)/18 = 4
Putting x= 4 in (*),
y = 3x - 15
= 3X4 - 15 = 12-15 = -3
Answer: x=4 and y = -3
Verification: We have used (2) for our finding the variables.So we use (1)for verification.
Putting x=4 and y = -3 in (1)
3x+5y=-3 ----(1)
LHS = 3X4 +5X(-3) = 12-15 = -3 =RHS
Therefore our values are correct.
I also need help using the combination method so maybe with these too:
1) 4x+5y=-2
5x=5-10y
2) 3y=16-2x
5x+2y=14
Combination method:
1) 4x+5y=-2
5x=5-10y
First of all see to it that both the equations are in the form Ax+By = C
The given equations are
4x+5y=-2 ----(1)X 2
5x+10y= 5 ----(2) (bringing -10y from the right side to the left side)
Observe that 5 and 10 are the coefficients of y respectively in the equations.
And their lcm is 10.
Why take the lcm? It is for equalising the coefficients of the variable we want to eliminate.
Since 5X2 = 10, multiply equation (1) through out by 2
8x+10y=-4 ----(3)
5x+10y= 5 ----(2)
(3) - (2)gives
(8x-5x) + 0 = (-4-5) (you may do vertical subtraction and get the answer faster)
3x = -9
x = -9/3 = -3
Putting x= -3 in (1),
4x+5y=-2 ----(1)
4X(-3) + 5y = -2
-12+5y = -2
5y = +12-2
5y = 10
y = 10/5 = 2
Answer: x = -3 and y = 2
Verification:Putting x = -3 and y = 2 in (2)
5x+10y= 5 ----(2)
LHS = 5x+10y
= 5X(-3)+10X2
=-15+20
=+5 =RHS which is correct
2) 3y=16-2x
5x+2y=14
The given equation are
2x+3y = 16 ----(1)X 2
5x+2y = 14 ----(2)X 3
(lcm of the coefficients of y is 6)
4x + 6y = 32 ----(3)
15x + 6y = 42 ----(4)
(3) - (4)implies
(4x-15x)+ (6y - 6y) = 32 - 42
-11x +0 = -10
-11x = -10
x = (-10)(-11) = 10/11
x=10/11 in (1)gives
2X(10/11) + 3y = 16
20/11 + 3y = 16
3y = 16-20/11
3y = (16X11-20)/11
3y = (176-20)/11
3y = 156/11
y = (3X52)/(3X11)
y = 52/11
Answer: x =10/11 and y = 52/11
Verification: Putting x =10/11 and y = 52/11 in 5x+2y = 14 ----(2)
LHS = 5x+2y
=5x(10/11) + 2X(52/11)
= 50/11 +104/11 =(50+104)/11 = 154/11 = (11X14)/11 = 14 =RHS which is correct
PLEASE NOTE:
The inequality problem has symbols like less than or equal to and greater than or equal and hence I have done the problem under a different application and I tried to copy it using print screen, copy, paste feature. It does not seem to work.Hence if you could give me your email address may be my attachment will work.
RELATED QUESTIONS
can you help me with this problem? i am solving using the substitution method y=3x+1... (answered by Alan3354)
I need help with this math homework problem It says solve the linear equation using the (answered by jim_thompson5910)
Hi, I need help to solve 3x – 5y = 15 by the substitution method.
y = 2x +... (answered by stanbon)
can you help me solve and check this problem using substitution method: (((x=1/5y... (answered by Fombitz)
i need help to solve this equation using the substitution method
4x-y= -1
3x+2y=... (answered by ankor@dixie-net.com)
Could you please help me. How can I solve this system of equation using the substitution (answered by jim_thompson5910)
Hello, I would like to know if someone can help me figure out how to do this type of... (answered by Ashley1516)
Hi i need major help on how to solve an equation using the substitution method the... (answered by stanbon)
Solve using the substitution method. Show your work. If the system has no solution or... (answered by Fombitz,Alan3354)