We need the following to be true
a+2b = -a
a+4 = 2a - 3b
Let's look at the first equation.
a + 2b = -a
Subtract both sides by a
2b = -2a
b = -a
Substitute b= -a into the second equation
a+4 = 2a + 3a
a + 4 = 5a
4a = 4
a = 1
Just take the negative of that and you get the value of b.
b = -1
Your solution is a=1 and b = -1.
Have an awesome day! :)
I believe the answer is 42 % which would be .42
The difference of the expression
is 
<h3>How to determine the difference?</h3>
The expression is given as:

Factor the denominators of the expressions:

Apply the difference of two squares to x² - 9

Take LCM

Hence, the difference of the expression
is 
Read more about expressions at:
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Answer: Equation: 0.5*30*b = 210
Base length: 14
Step-by-step explanation: The formula of the area of a triangle is 1/2*b*h, so we can use that and the information given to make a formula then solve.