Question

(___ −2a)2 = 9b2− ___ + ___

Answer 1

`\large\boxed{(3b-2a)^2=9b^2-12ab+4a^2}`

Explanation:

`\text{Use}\ (a-b)^2=a^2+2ab+b^2\\\\(x-2a)^2=x^2-(2)(x)(2a)+(2a)^2=9b^2-\underline{\ \ \ \ }+\underline{\ \ \ \ }\\\\\text{Therefore}\ x^2=9b^2\\\\x^2=3^2b^2\\\\x^2=(3b)^2\to x=3b\\\\(3b-2a)^2=(3b)^2-(2)(3b)(2a)+(2a)^2=9b^2-12ab+4a^2`