Question 557225: what is the step by step way to sove this equation? 8y-10*2<10y-3*5
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! equation is:
8y - 10*2 < 10y - 3*5
simplify to get:
8y - 20 < 10y - 15
add 20 to both sides of the equation to get:
8y < 10y + 5
subtract 10y from both sides of the equation to get:
-2y < 5
divide both sides of the equation by -2 to get:
y > -(5/2)
note that when you multiply or divide both sides of an inequality by a negative number, the inequality reverses.
your solution is:
y > -(5/2)
to confirm, substitute values of y in your original equation to see if the equation holds true or not.
pick a value for y smaller than -(5/2), equal to -(5/2), and greater than -(5/2)
pick values that are easy to calculate.
i would pick y = -3, y = -(5/2), y = -2
your original equation is:
8y-10*2 < 10y - 3*5
simplify this to get:
8y-20 < 10y-15
when y = -3, this equation becomes:
8*(-3)-20 < 10*(-3)-15 which becomes:
-24-20 < -30-15 which becomes:
-44 < -45 which is false, as it should be, because y is not greater than -(5/2) in this case.
when y = -(2/5), the equation of:
8y-20 < 10y-15 becomes:
8*(-5/2)-20 < 10*(-5/2)-15 which becomes:
(-40/2)-20 < (-50/2)-15 which becomse:
(-40/2)-(40/2) < (-50/2)-(30/2) which becomes:
-80/2 < -80/2 which is false, as it should be, because y is not greater than -(5/2) in this case. it is equal to -(5/2).
when y = -2, the equation of:
8y-20 < 10y-15 becomes:
8*(-2)-20 < 10*(-2)-15 which becomes:
-16-20 < -20-15 which becomes:
-36 < -35 which is true, as it should be, because y is greater than -(5/2) in this case.
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