1)which of these systems of linear equations has an infinite number of solutions? a)3x-8y=21 6x-16y=46 b)3x+6y=22 6x+12y=44 c)5x+7y=24 10x-14y=48 d)5x-9y=20 10x+18y=40 2)consider the system of linear equations? 5x+10y=15 10x+3y=13 to use the linear combination method and addition to eliminate the x-terms, by which number should the first equation be multiplied a)-2 b)-1/2 c)1/2 d)2