Practice problem
Simplify by combining like terms. x+2y+3z+4x+5y+6zx+2y+3z+4x+5y+6zx+2y+3z+4x+5y+6z
7x+7y+7z7x+7y+7z7x+7y+7z
5x+7y+9z5x+7y+9z5x+7y+9z
21xyz21xyz21xyz
5x2+7y2+9z25x^2+7y^2+9z^25x2+7y2+9z2
Type a concept, like “slope” or “photosynthesis”.