Subtract 5x^2+8x-11 from 3x^2+8x-7

-2x^2+4

Explanation: First you’d need to rewrite the equation as (3x^2+8x-7)-(5x^2+8x-11). Then since you are subtracting, distribute the negative to the right side which will then give you -5x^2-8x+11 since you flip the signs. Then simply combined like terms. -5x^2 + 3x^2 is -2x^2. Then 8x-8x is 0 and lastly, +11-7 is 4. So in order, all together, your answer is -2x^2+4.