Answer:
a = 5
Step-by-step explanation:
First re-write the equation in standard form by using distributive property to get rid of grouping symbols, and ordering the terms of the trinomial with leading term first and on one side of the equal sign, while zero on the other:
[tex]-2(x+1)+5x^2+12=15\\-2x-2+5x^2+12-15-0\\5x^2-2x-5=0[/tex]
Therefore, the coefficient "a" that accompanies the leading term, is "5"
