I need help with this- thank you

Will mark brainliest! :)

(X^2 + 2x + 7) + (4x^2 + x - 3) =

x^2 + 2x + 7 + 4x^2 + x - 3 =

5x^2 + 3x + 4

no because mercury has a density of 13.6 grams per centimeter squared while gold has 19.32 grams centimeter squared

step-by-step explanation:

1. 16.64

a^2+b^2=c^2

pr^2=pq^2+qr^2

pr^2=14^2+ 9^2

pr^2=196+81

pr= sqr root of 277

16.64

2. 11.31

c^2-a^2=b^2

18^2- 14^2=b^2

b^2=324-196

b=sqr root of 126

b=11.31

hope it ! (btw im in connections academy to, good luck! )