Question 137243
can you please solve this by the substitution method?
y - 2x = -7.5
3x - 5y = 3.2
:
Arrange the 1st equation for substitution:
y - 2x = -7.5 
y = 2x - 7.5; added 2x to both sides:
:
In the 2nd equation, substitute (2x-7.5) for y, solve for x
3x - 5(2x-7.5) = 3.2
:
3x - 10x + 37.5: multiply what's inside the brackets (neg outside changes signs inside the brackets)
:
3x - 10x = 3.2 - 37.5; subtracted 37.5 from both sides
:
-7x = -34.3
x = {{{(-34.3)/(-7)}}}
x = +4.9
:
Use the equation we derived from the 1st equation to find y:
y = 2x - 7.5
:
Substitute 4.9 for x
y = 2(4.9) - 7.5
;
y = 9.8 - 7.5
:
y = 2.3
:
:
Check solutions by substitution in the 2nd equation:
3x - 5y = 3.2 
3(4.9) - 5(2.3) = 
14.7 - 11.5 = 3.2, confirms our solution
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Do you think you can do these kind of problems now?