a. 147-7(x-13)=98
To solve this equation, we will first distribute the -7 to the terms inside the parentheses:
147 - 7x + 91 = 98
Next, we will combine like terms:
238 - 7x = 98
Now, we will isolate the variable by subtracting 238 from both sides:
-7x = -140
Finally, we will solve for x by dividing both sides by -7:
x = 20

b. 215-3(x+8)=140
To solve this equation, we will first distribute the -3 to the terms inside the parentheses:
215 - 3x - 24 = 140
Next, we will combine like terms:
191 - 3x = 140
Now, we will isolate the variable by subtracting 191 from both sides:
-3x = -51
Finally, we will solve for x by dividing both sides by -3:
x = 17

c. 125-12(x-17)=89
To solve this equation, we will first distribute the -12 to the terms inside the parentheses:
125 - 12x + 204 = 89
Next, we will combine like terms:
329 - 12x = 89
Now, we will isolate the variable by subtracting 329 from both sides:
-12x = -240
Finally, we will solve for x by dividing both sides by -12:
x = 20