Is f(x)=square root of x^2 - 9 an even function

Which linear equations have an infinite number of solutions? check all that apply.  (x  –  3/7)  =  2/7(3/2x  –  9/14)8(x  +  2)  =  5x  –  1412.3x  –  18  =  3(–6  +  4.1x)(6x  +  10)  =  7(x  –  2)4.2x  –  3.5  =  2.1 (5x  +  8)

Which shows a reasonable estimation for 124% of 42 using the distributive property?

Which linear function represents the line given by the point-slope equation y + 1 = –3(x – 5)?