Answer:
7x+21 = 7x + 21
Step-by-step explanation:
7(x+3)=6-(-7x - 15)
L.H.S
=7(x+3)
=7x+21 (multiply 7 by (x+3))
R.H.S:
=6-(-7x - 15)
= 6+7x+15 (multiply the -ive sign in the bracket)
= 7x + 21 ( adding 15 and 6)
now compare the two sides
7x+21 = 7x + 21 hence we prove that L.H.S= R.H.S
