Q. Use Pascal's Triangle to expand (3x−5z)3. Express your answer in simplest form.Answer:
Identify Row of Pascal's Triangle: Identify the row of Pascal's Triangle that corresponds to the exponent 3. The third row of Pascal's Triangle (starting with row 0) is 1,3,3,1.
Write Binomial Coefficients: Write out the terms using the binomial coefficients from Pascal's Triangle.The expansion of (a−b)3 using the binomial theorem is given by:1⋅a3+3⋅a2⋅b+3⋅a⋅b2+1⋅b3
Substitute Variables: Substitute a with 3x and b with −5z in the expansion.The terms become:1⋅(3x)3+3⋅(3x)2⋅(−5z)+3⋅(3x)⋅(−5z)2+1⋅(−5z)3
Calculate Each Term: Calculate each term.1∗(3x)3=1∗(27x3)=27x33∗(3x)2∗(−5z)=3∗(9x2)∗(−5z)=−135x2z3∗(3x)∗(−5z)2=3∗(3x)∗(25z2)=225xz21∗(−5z)3=−125z3
Combine Terms: Combine the terms to get the final expanded form.The expanded form is:27x3−135x2z+225xz2−125z3
More problems from Pascal's triangle and the Binomial Theorem