Answer:
Step-by-step explanation:
Multiplying Equation A by (1/3) and adding the result to Equation B will do the trick. Let's actually solve the problem!
Equation A: (5/3)x + 3y = 12
Equation B: 4x - 3y = 8
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(5/3 + 12/3)x = 15 Note how this has eliminated the variable
(17/3)x = 15 y.
x = (3/17)(15)
Answer: 
Step-by-step explanation:
Using the data given in the exercise, we can draw the diagram attached, where "h" is the height of the building reached by the top of the ladder.
Notice that there are two similar triangles.
So, you can set up the following proportion:

Finally, in order to calculate the height on the building reached by the top of the ladder, you must solve for "h".
Therefore, the value of "h" is :

Yes, you need to make the denominators the same. 2/3 becomes 8/12. So now you add 7/12 and 8/12, getting 15/12. But you're not done you need to simplify 15/12. The answer is 1 1/4.