Nthe right triangle above, a= 9.9 and c= 12.4 find the value of b, rounded to the nearest tenth.

In order to solve this equation, use the Pythagorean Theorem.

So... a^2 + b^2 = c^2

9.9^2 + b^2 = 12.4^2

98.01 + b^2 = 153.76

b^2 = 55.75

Take the square root of both sides 

b is approximately 7.466, round to tenth place and it's 7.5.

First subtract 10 from both side
y^2+6y-16=0
(y+8)(y-2)=0
-8 and 2