22 баллов за полное решение и правильное алгебра 8 класс 4 и 5 задание
4. а) {-4x≤-12 {3x≤15 -4x≤ -12 3x≤15 x≥3 x≤5 {x≥3 {x≤5 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ------------ 3 ------------- 5 -------------- //////////////////////////////////// x∈[3; 5] Ответ: [3; 5]. б) {0.5x+2>1 {3x-1.6<0.8<br> 0.5x+2>1 3x-1.6<0.8<br>0.5x>1-2 3x<0.8+1.6<br>0.5x> -1 3x<2.4<br>x> -2 x<0.8<br>{x>-2 {x<0.8<br> \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ----------- -2 -------------- 0.8 ---------------- ////////////////////////////////////// x∈(-2; 0.8) Ответ: (-2; 0.8). в) {(x+2)(2-x)<(x+3)(4-x)<br> {(5+x)/4 + (1-2x)/6 ≥1 (x+2)(2-x)<(x+3)(4-x) (5+x)/4 + (1-2x)/6≥1<br>4-x²<4x+12-x²-3x 3(5+x)+2(1-2x)≥12<br>-x<12-4 15+3x+2-4x≥12<br>-x<8 -x≥12-17<br> x> -8 -x≥ -5 x≤5 {x>-8 {x≤5 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ---------- -8 --------------- 5 ------------ //////////////////////////////////// x∈(-8; 5] Ответ: (-8; 5]. 5. {3x>12 {x {x>4 {x a∈(-∞; 4) Ответ: (-∞; 4).
спасибо большое
