Answer:
b=2 or b=-2.5
Explanation:
We solve absolute value equations the same as any other equation using inverse operations. However, the inverse operation for absolute value requires one special condition. Since absolute values change a number to a positive regardless if it has a negative sign, we have two possible answers. When we have the absolute value operation isolated, we will set it equal to both the negative and positive option.
![-10-|1+4b|=-19\\-10+10-|1+4b|=-19+10\\-|1+4b|=-9\\(-|1+4b|)/(-1) =(-9)/(-1) \\|1+4b|=9](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ezaa9ecdqui0em84jb9kccpkpqok2gfweb.png)
We now have the absolute value isolated. We will set it equal to both 9 and -9.
![1+4b=9\\1-1+4b=9-1\\4b=8\\b=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/vlj6wdhv0js6n8uxwhje9hjqm0ki12mk40.png)
and
![1+4b=-9\\1-1+4b=-9-1\\4b=-10\\b=(-10)/(4)=(-5)/(2)= -2.5](https://img.qammunity.org/2019/formulas/mathematics/middle-school/bpnh4of5r8qa6uqopbtvudoq44js3th86f.png)