Doug C. answered • 09/27/24
Math Tutor with Reputation to make difficult concepts understandable
There are two basic strategies to solve for x in this linear equation in one variable.
One is to distribute the 3 over the (3x - 7) combine similar terms, isolate the terms containing the variable, then divide both sides by that term's numerical coefficient.
The second is to realize that every term of this equation is divisible by 3. Do that first then follow a similar pattern for the 1st method.
Here is what those looks like.
Distribute:
9x - 21 + 3x = 39
12x - 21 = 39
12x = 60 (add 21 to booth sides)
x = 60/12 = 5
Divide by 3 1st:
3x - 7+ x = 13
4x - 7 = 13
4x = 20
x = 20/4 = 5
Check:
3[3(5) - 7] +3 (5) =? 39
3[8] + 15 ?= 39
24 + 15 ?= 39
39 = 39 check
