Answer:
x=7/2i, -7/2i
Step-by-step explanation:
4x^2+49=0
4(x^2+49/4)=0
x^2+49/4=0/4
x^2+49/4=0
x^2=0-49/4
x^2=-49/4
take the square root of -49/4, you'll get imaginary numbers because of the negative sign.
