Simplify the following polynomials. Arrange the simplified
form in
descending order with respect to X.
a. 6x²y+4x³y²- 10x²y–15x³y²
=-11x³y²- 4x²y
b. 2(7x²- y²)+4(x³+9y)
= 14x² - 2y +4x³+36 y
= 4x³+14x² + 34 y
c.6x⁴+ 4x-11x²-x³ +7+8x
=-6x⁴- x³-11x² +12x+7
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