(b) Solve: using factorisation method: x² – 3x - 10 = 0
Answers
Step-by-step explanation:
Use the quadratic formula
=−±2−4√2
x=\frac{-{\color{#e8710a}{b}} \pm \sqrt{{\color{#e8710a}{b}}^{2}-4{\color{#c92786}{a}}{\color{#129eaf}{c}}}}{2{\color{#c92786}{a}}}x=2a−b±b2−4ac
Once in standard form, identify a, b and c from the original equation and plug them into the quadratic formula.
2−3−10=0
x^{2}-3x-10=0x2−3x−10=0
=1
a={\color{#c92786}{1}}a=1
=−3
b={\color{#e8710a}{-3}}b=−3
=−10
c={\color{#129eaf}{-10}}c=−10
=−(−3)±(−3)2−4⋅1(−10)√2⋅1
x=\frac{-({\color{#e8710a}{-3}}) \pm \sqrt{({\color{#e8710a}{-3}})^{2}-4 \cdot {\color{#c92786}{1}}({\color{#129eaf}{-10}})}}{2 \cdot {\color{#c92786}{1}}}x=2⋅1−(−3)±(−3)2−4⋅1(−10)
2
Simplify
Evaluate the exponent
Multiply the numbers
Add the numbers
Evaluate the square root
Multiply the numbers
=3±72
x=\frac{3 \pm 7}{2}x=23±7
3
Separate the equations
To solve for the unknown variable, separate into two equations: one with a plus and the other with a minus.
=3+72
x=\frac{3+7}{2}x=23+7
=3−72
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