Answer:
Equation: 5x+x=84
Leah's dog weighs 14 lbs
Darlene's dog weighs 70 lbs
Explanation:
Let's let x=# of pounds/weight of Leah/s dog, so our equation would be:
5x + x=84, since both dogs together equal 84 pounds
5x=Darlene's dog and x=Leah's dog
Simplify by adding both x's, so that makes 6x=84
Divide BOTH sides by 6 to isolate x for: x=14 pounds
BUT, x is only the weight of Leah's dog, so we plug in 14 for x in 5x to get the weight of Darlene's dog; 70 pounds
You could check your answer by adding both weights up: 70+14=84 (check!)