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Could someone help me with these math problems? I can't figure them out. Solve the linear equation;
x+2y=15
y=-2x+0 9x-12y=-3
-12x+16y=4? 15.00g of Si reacts with 25.00g of F2 to produce 28.67g of SiF4. Which reactant is the limiting reagent? Find all of the actual roots of the polynomial: x^3 - 2x^2 + 5x + 26 = 0? How long does Equazen supplement really take to make effect in adults with inattentive adhd? Has someone tested it? 7^(x+1) + 7^x + 7^(x-1) = 399, what is x?