Solve the simultaneous equations: 4x + 2y = 26 and 3x + 3y = 21

Let eq 1 = 4x + 2y = 26 eq 2 = 3x + 3y = 21 Using the elimination method: You need to make either the xs or ys have the same constant term in both equations( sign does not matter). In this case, we will make the constant be the same for both ys. To do this, find a common multiple of 2 and 3. I have chosen 6. To go from 2 to 6, you multiply by 3. Thus, you must multiply all of eq 1 by 3 --> 12x + 6y = 78. In eq 2 , the constant for y is 3, thus you have to multiply by 2 to get 6. Multiplying eq2 by 2 and you get --> 6x + 6y = 42.Next, you either subtract or add the two equations together. Since the y in both equations share the same sign, you subtract equation 2 from equation 1 (same-sign-subtract). 12x-6x = 6x 6y-6y = 0 78-42 = 36 Resulting in 6x = 36 x = 6 Substitute x into one of the original equations. 3(6) + 3y = 21 3y = 21-18 3y = 3y = 1 Therefore x = 6, y = 1

Answered by Dermot N. Maths tutor

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