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how do you solve a system of equations using elimination

 

t=77+3h

t=92+2h

 Nov 30, 2016
 #1
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Solve the following system:
{t = 2 h + 92 | (equation 1)
t = 3 h + 77 | (equation 2)
Express the system in standard form:
{t - 2 h = 92 | (equation 1)
t - 3 h = 77 | (equation 2)
Subtract equation 1 from equation 2:
{t - 2 h = 92 | (equation 1)
0 t - h = -15 | (equation 2)
Multiply equation 2 by -1:
{t - 2 h = 92 | (equation 1)
0 t+h = 15 | (equation 2)
Add 2 × (equation 2) to equation 1:
{t+0 h = 122 | (equation 1)
0 t+h = 15 | (equation 2)
Collect results:
Answer: |t = 122                 and                    h=15
 

 Nov 30, 2016
 #2
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Source: http://www.coolmath.com/algebra/12-2x2-systems-of-equations/03-solving-by-elimination-addition-01

 

t = 77 + 3h 

t = 92  + 2h 

 

the point of elimination is to eliminate one of the variables in the system of equations.

 

Lets eliminate t 

 

    t = 77 + 3h 

- 1(t = 92 + 2h)     multiply by -1

 

    t= 77 + 3h        now add the two equations

+ -t= -92 - 2h

    0 = -15 +h

h = 15

 

Now plug in 15 for h in order to solve for t. 

 

t = 77 + 3 (15) = 77 + 45 = 122    

 

So then now we know    t =122 and h =15

 Nov 30, 2016

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