In these types of problems, the first step is to combine like terms. Like terms are terms with the same exponent (power), and the same variable (like all x's). In the above equation, we can combine -5x, 2x and -3y. Let's do it:

The next step would be to factor out the common ratio, which is not applicable here, so your answer would be
-6x + 7y. Hope this helps!
Answer:
15 + 23 = 38
38 x 9 = 342
342 x 1/2 (basically just dividing by 2) 171
Step-by-step explanation:
Formula of a trapezoid:
B1(base 1) + B2(base 2) x H(height) x 1/2(basically just dividing by 2)
In this case,
12 and 23 are your bases, 9 is your height.
I may not fully understand the question but the value of 7 is 7. The value of 6 is 6 and the value of 9 is 9.