Answer:
(a)[tex]20+(-9)+8+(-7)[/tex]
(b)[tex]4x+(-7y)+(-5z)+6[/tex]
Step-by-step explanation:
We are required to write an equivalent expression that uses only addition for each of the given term.
Note that the product of + and - is always -.
Therefore:
(a)20−9+8−7
[tex]20-9+8-7 \\=20+(-9)+8+(-7)[/tex]
(b)4x−7y−5z+6
[tex]4x-7y-5z+6\\=4x+(-7y)+(-5z)+6[/tex]