Question 168588
1. 16-m^2
(4+m)(4-m)
2. 9a^2b^2-100
(3ab+10)(3ab-10)
3. a^2-36+169
Using the quadratic equation {{{a=(-b+-sqrt(b^2-4*a*c))/(2*a)}}}  we get
a=(36+-sqrt[-36^2-4*1*169])/281
a=(36+-sqrt[1,296-676])/2
a=(36+-sqrt620)/2
a=(36+-24.9)/2
a=(36+24.9)/2
a=60.9/2
a=30.45 ans.
a=(36-24.9)/2
a=11.1/2
a=5.55 ans.
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I'll leave the rest for you to practice with.
4.9x^2+48x+64
5.45-80y^2
6. 15a^2-31ab+10b^2