Question

s-7t=-42 & s-3t=6 find the value x and y in substitution method

Answer 1

Answer:

I cant give the answer but i can help set it up

Step-by-step explanation:

s-7t=42 & s-3t=6

take s-3t=6

          +3T = +3T - BASICALLY you add 3t to 6 and take it out of the left side

so it now is s=6+3t - now that s is equal to 6+3t you can put 6+3t into s-7t=42 inplace of s.  like so 6 + 3t - 7t = 42.  then just subtract 7t from 3t which is - 4t

6+ -4t = 42  now subtract 6 from 42 to get -4t = 36

now divide 36 by - 4 which = t= -9    - now that t = -9 put -9 in for t in the

s-7t=42 and solve like a normal equation.  

Answer 2

Solution :

Given s - 7t = - 42

=> s = 7t - 42 ---( 1 )

and s - 3t = 6 -----( 2 )

Substitute ( 1 ) in equation ( 2 ), we get

=> 7t - 42 - 3t = 6

=> 4t = 6 + 42

=> 4t = 48

=> t = 48/4

=> t = 12

Now ,

put t = 12 in equation ( 1 ) we get

s = 7 × 12 - 42

= 84 - 42

= 42

Therefore ,

t = 12 , s = 42

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