What is the sum of #3x^2 + x + 8# and #x^2 - 9#?

1 Answer
Mar 14, 2016

#4x^2 + x - 1 #

Explanation:

To obtain the sum of : # 3x^2 + x + 8 + x^2 - 9 #

#color(blue)" collect like terms "#

like terms are terms with the 'same' variable and power.

example : # 5x^2 " and " 8x^2 " are like terms " #

but # 6x^2 " and " 3x " are not " #

In the above expression # 3x^2 " and " x^2 " are like terms "#
and can be collected by adding their coefficients ( the number values in front of them).

the x term has no other terms with only x in them, and numbers are summed in the normal way.

#rArr 3x^2+x+8+x^2-9 = 4x^2 + x - 1 #