а)4x^2-x^2+6xy-9y^2=3x^2+6xy-9y^2=3(x^2+2xy-3y^2)
б)(4a^2+28ab+49b^2)-(9a^2-30ab+25b^2)= -5a^2+58ab+24b^2
а)4x^2-x^2+6xy-9y^2=3x^2+6xy-9y^2=3(x^2+2xy-3y^2)
б)(4a^2+28ab+49b^2)-(9a^2-30ab+25b^2)= -5a^2+58ab+24b^2