Skills 3: Substitution with Variables Qns 1-5: Evaluate the following expressions when S = 8 and T = 4 1) 2) S + T = 8+4= S–T= 12 3) 4) 𝐒 𝐓 5) ST + S = 𝟖 = =𝟐 𝟒 2ST – T = (2 x 8x 4)- 4= Qns 6-10: Substitute the following values into the expressions and calculate the answer: a = 3 b = 5 c = 8 d = 10 6) 7) a+b= 8) 9) d–c= 𝐝 𝐛 cd + ab = (8x10) +(3 x 5)=80 +15 = = 10) 3ad – 2bc = Qns 11-15: Substitute the following values into the expressions and calculate the answer: d = -2 e = 6 x = -4 y = 7 11) e–y= 12) 2d – x = 13) 𝟑𝐞 𝐱𝐲 𝟏𝟖 −𝟐𝟖 = 𝟑𝐱𝟔 −𝟒𝐱 𝟕 −𝟏𝟖 = = 𝟐𝟖 −𝟗 = = 𝟏𝟒 14) (2dx) + (de) = (2 x -2 x -4) +(-2 x 6)= 16+-12 = 16 -12 = 4 15) -3x – dy = Extension Qns 16-20: Rewrite the following table of values and fill it out, using the rule from each question: x y 16) y=x+4 3|Page 17) -2 -1 18) y = 3x 0 1 2 19) y = 3x – 2 20) y = -4x + 6 y= 4|Page 𝐱 𝟐