Question

Use the quadratic formula to solve x2 + 7x + 8 = 0. Estimate irrational solutions to the nearest tenth.

Answer 1

x2 + 7x + 8
a = 1
b = 7
c = 8
x = [-b +-sq root (b^2 -4ac)] / 2a
x = [-7 +- sq root (49 -4*1*8)] / 2*1
x = [-7 +- sq root (49 -32)] / 2
x = [-7 +sq root (17)] / 2

x1 = [-7 +sq root (17)] / 2
x2 = [-7 -sq root (17)] / 2

x1 = -1.4384
x2 = -5.5616