Answer:
for the first photo the answer is 5x + 6(-x + 4) = 13
Step-by-step explanation:
if y equals to -x +4
then replace the y in this equation: 5x + 6y = 13 with this ( -x +4 ) its simple.
I cannot answer the other 2 photos at the moment but ill see if I can whenever else I have time.
15
Answer: 3 (c)
2 * 3 = 6 therefore 15 * 3 = 45$
3 * 2 = 6 therefore 21 * 2 = 42$
36
1. Cross Multiply.
2. Solve.
3. Your answer is 36