Question

Solve 2x^2 – 8x = –7

Answer 1

`\displaystyle 2x^2 - 8x = - 7 \\ \\ 2x^2-8x+7=0 \\ \\ \Delta=b^2-4ac \\ \\ \Delta=(-8)^2-4\cdot2\cdot7 \\ \\ \Delta = 8 \\ \\ X_(1,2)= (-b\pm √(\Delta) )/(2a) = (8 \pm 2 √(2) )/(4) = (\\ot2(4\pm √(2)) )/(\\ot4) = (4\pm √(2) )/(2)`

Answer 2

Making one side of the equation zero, the equation becomes,
2x² - 8x + 7 = 0
The value of x may be calculated through the quadratic formula.
x = (-b +/- sqrt(b² - 4ac)) / 2a
where a, b, and c are 2, -8, and 7, respectively. The values are,
x = (8 + sqrt (8² - (4)(2)(7))) / 2x2 = -1.29
x = (8 - sqrt (8² - (4)(2)(7))) / 2x2 = -2.71