4(2x+5) = 3(x+15) Using substitution... how?
Mathematics · High School · Tue Nov 03 2020
Answered on
To solve for the value of x in 4(2x+5) = 3(x+15), simplify first the both sides of the equation.
4(2x+5) = 3(x+15)
The next step is to distribute 4 to 2x and 5; 3 to x and 15
4(2x+5) = 3(x+15)
> 4(2x) +4(5) = 3(x)+3(15)
> 8x+20 = 3x+45
Then, subtract 3x to the both sides of the equation;
> 8x+20−3x = 3x+45−3x
> 5x+20= 45
Next is to subtract 20 to the both sides.
> 5x+20−20= 45−20
> 5x= 25
Lastly, divide both side by 5 to get the value of x.
> 5x= 25
> 5x/5= 25/5
> x =5
You can check the answer by substituting the value of x.
> 4(2x+5) = 3(x+15)
> 4(2(5)+5) = 3(5+15)
> 4(10+5) = 3(20)
> 4(15) = 60
> 60 = 60.
Therefore, x =5 is correct.