The problem asks us to find the solution set for each of the given quadratic equations using the quadratic formula. The equations are: a) $2x^2 - 7x + 1 = 0$ b) $3x^2 = -9x + 2$ c) $x^2 - 4x = 3$ d) $x^2 = x + 5$

AlgebraQuadratic EquationsQuadratic FormulaSolution Sets
2025/6/1

1. Problem Description

The problem asks us to find the solution set for each of the given quadratic equations using the quadratic formula. The equations are:
a) 2x27x+1=02x^2 - 7x + 1 = 0
b) 3x2=9x+23x^2 = -9x + 2
c) x24x=3x^2 - 4x = 3
d) x2=x+5x^2 = x + 5

2. Solution Steps

The quadratic formula is given by:
x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
a) 2x27x+1=02x^2 - 7x + 1 = 0. Here, a=2a = 2, b=7b = -7, and c=1c = 1.
x=(7)±(7)24(2)(1)2(2)=7±4984=7±414x = \frac{-(-7) \pm \sqrt{(-7)^2 - 4(2)(1)}}{2(2)} = \frac{7 \pm \sqrt{49 - 8}}{4} = \frac{7 \pm \sqrt{41}}{4}.
The solution set is {7+414,7414}\{\frac{7 + \sqrt{41}}{4}, \frac{7 - \sqrt{41}}{4}\}.
b) 3x2=9x+23x^2 = -9x + 2. First, rewrite the equation in standard form: 3x2+9x2=03x^2 + 9x - 2 = 0. Here, a=3a = 3, b=9b = 9, and c=2c = -2.
x=9±924(3)(2)2(3)=9±81+246=9±1056x = \frac{-9 \pm \sqrt{9^2 - 4(3)(-2)}}{2(3)} = \frac{-9 \pm \sqrt{81 + 24}}{6} = \frac{-9 \pm \sqrt{105}}{6}.
The solution set is {9+1056,91056}\{\frac{-9 + \sqrt{105}}{6}, \frac{-9 - \sqrt{105}}{6}\}.
c) x24x=3x^2 - 4x = 3. First, rewrite the equation in standard form: x24x3=0x^2 - 4x - 3 = 0. Here, a=1a = 1, b=4b = -4, and c=3c = -3.
x=(4)±(4)24(1)(3)2(1)=4±16+122=4±282=4±272=2±7x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4(1)(-3)}}{2(1)} = \frac{4 \pm \sqrt{16 + 12}}{2} = \frac{4 \pm \sqrt{28}}{2} = \frac{4 \pm 2\sqrt{7}}{2} = 2 \pm \sqrt{7}.
The solution set is {2+7,27}\{2 + \sqrt{7}, 2 - \sqrt{7}\}.
d) x2=x+5x^2 = x + 5. First, rewrite the equation in standard form: x2x5=0x^2 - x - 5 = 0. Here, a=1a = 1, b=1b = -1, and c=5c = -5.
x=(1)±(1)24(1)(5)2(1)=1±1+202=1±212x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4(1)(-5)}}{2(1)} = \frac{1 \pm \sqrt{1 + 20}}{2} = \frac{1 \pm \sqrt{21}}{2}.
The solution set is {1+212,1212}\{\frac{1 + \sqrt{21}}{2}, \frac{1 - \sqrt{21}}{2}\}.

3. Final Answer

a) {7+414,7414}\{\frac{7 + \sqrt{41}}{4}, \frac{7 - \sqrt{41}}{4}\}
b) {9+1056,91056}\{\frac{-9 + \sqrt{105}}{6}, \frac{-9 - \sqrt{105}}{6}\}
c) {2+7,27}\{2 + \sqrt{7}, 2 - \sqrt{7}\}
d) {1+212,1212}\{\frac{1 + \sqrt{21}}{2}, \frac{1 - \sqrt{21}}{2}\}