Hey there!
4x + 3x = -21
7x = -21
x = -21/7
x = -3
Hope it helps ya!
Answer:
[tex]4x + 3x = - 21[/tex]
[tex]7x = - 21[/tex]
[tex]x = \cancel \frac{ - 21}{7} [/tex]
[tex]x = - 3[/tex]
