Answer: Choice D) 
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Work Shown:

Explanation:
First I subtracted y/b from both sides. Then I multiplied both sides by 'a' to fully isolate x. You can optionally distribute the 'a' through to each term inside the parenthesis, but your teacher has chosen not to do this.
Answer:
Acute isosceles triangle
Step-by-step explanation:
because an acute angle is more than 45 but less then 90.
that's all i know sorry!
Answer:
x = 15
Step-by-step explanation:
f(x) = 4x² + 7x
= 4(-3)² + 7(-3)
= 36 + (-21)
= 15