Question 1210382: Solve: 45x + 30 = 120
x = 12
x = 10
x = 6
x = 2
Found 3 solutions by josgarithmetic, ikleyn, Edwin McCravy:
Answer by josgarithmetic(39616)   (Show Source):
Answer by ikleyn(52775)  (Show Source):
You can put this solution on YOUR website! .
Solve: 45x + 30 = 120
~~~~~~~~~~~~~~~~~~~~~~
It is a standard and typical linear equation in one unknown
for a beginner student to start learning the subject.
The standard mantra to solve is as follows:
subtract '30' from both sides. You will get
45x = 120-30,
45x = 90.
Now divide both sides by 45. You will get
x =  = 2.
ANSWER. The solution to given equation is x = 2.
CHECK. We substitute x= 2 into the left side of the given equation. It gives the value
45*2 + 30 = 90 + 30 = 120,
the same as the right side of the given equation.
This check CONFIRMS that the solution x = 2 is CORRECT.
Solved, with explanations and explicit check.
Knowing the methodology, you can solve a million of other similar problems/equations.
Answer by Edwin McCravy(20054)  (Show Source):
You can put this solution on YOUR website!
Solve: 45x + 30 = 120
x = 12
x = 10
x = 6
x = 2
I think that this student may have only gotten to the stage of finding
solutions by trial and error by substitution.
Try x = 12
45x + 30 = 120
45(12) + 30 = 120
540 + 30 = 120
570 = 120, so x = 12 is NOT the correct answer.
Try x = 10
45x + 30 = 120
45(10) + 30 = 120
450 + 30 = 120
480 = 120, so x = 10 is NOT the correct answer.
Try x = 6
45x + 30 = 120
45(6) + 30 = 120
270 + 30 = 120
300 = 120, so x = 6 is NOT the correct answer.
Try x = 2
45x + 30 = 120
45(2) + 30 = 120
90 + 30 = 120
120 = 120, so x = 2 IS the correct answer.
Edwin
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